The burning question: Was Mike Deaver trying to prove Ed Rollins' point about "the sin of arrogance" at Lesley Stahl's party last week for her CBS colleague Bill Plante and his fiance'e, NBC's Robin Smith?

When Deaver's lobbying problems on behalf of the Canadian government hit front pages this spring, Rollins told The New York Times that it isn't what people do in Washington that brings them down, "it's the sin of arrogance."

Deaver was deputy chief of staff when he left the White House in 1985, about the same time Rollins left as assistant to the president for political and intergovernmental affairs. Both are in private business now, Rollins as a lobbyist and political consultant and Deaver as a lobbyist and public relations consultant.

Since neither had bothered to keep in touch with the other, the first time they saw each other in more than a year was at Stahl's party.

Deaver brought his wife Carolyn and Rollins brought his fiance'e Sherrie Sandy, director of communications for the Oliver T. Carr Co. Stahl seated Rollins and Carolyn Deaver together at one table, and at another put Deaver between the future Mrs. Rollins, whom he hadn't met before, and Independent News Network correspondent Jan Smith, who is married to ABC's Sam Donaldson.

Deaver displayed his way with words during the toasts when he told everybody:

"You can tell how far from power I've fallen in a year when I'm seated between Ed Rollins' fiance'e and Sam Donaldson's wife."

A moment of awkward silence was followed by the rapid departure of Rollins and Sandy. Carolyn Deaver quickly gathered up Mike and went home, while the Donaldsons stayed on to enjoy what was left of the party.

Don't expect her to bring you back a piece of the wedding cake, but do expect to pick up the tab for Nancy Reagan's trip to the royal wedding tomorrow in London.

A White House spokesman said yesterday that the State Department is paying for the trip, even though Mrs. Reagan is not an official U.S. representative to the wedding as she was in 1981 when Prince Charles and Princess Diana were married. Because Buckingham Palace is calling the wedding a "private" family affair, Mrs. Reagan is a guest of Queen Elizabeth II -- though not to the extent that the queen foots her bills.

"Mrs. Reagan is not there as a representative of the government, but in the role of first lady she does represent the American people," said Betsy Koons, her deputy press secretary. "As first lady she doesn't travel anywhere strictly privately."

Perhaps to avoid the excesses reported from that other royal wedding, Mrs. Reagan jetted off to London Sunday aboard an Air Force Boeing 707 without a press corps.

In 1981, Mrs. Reagan's clothes and activities commanded almost as many headlines as the royal couple's, and in the process she earned the much-loathed "Queen Nancy" moniker that took a team of White House image makers months -- nay, years -- to undo.

This time, hoping for a minimum of attention, the White House will not announce until tomorrow what Mrs. Reagan will wear to the wedding or what the Reagans are giving (and the State Department is paying for) to Prince Andrew and Lady Sarah.

But Mrs. Reagan didn't manage to slip into Heathrow Airport unnoticed Sunday night. In addition to U.S. Ambassador Charles Price and his wife Carol, awaiting her were a small army of reporters and a security detail that included marksmen positioned on the rooftops.

Mrs. Reagan's entourage is impressive, including 20 Secret Service agents, a chief of staff, press secretary, deputy press secretary, administrative assistant, director of scheduling and events, White House photographer, White House medic, hairdresser and personal maid.

Last night Mrs. Reagan was invited to a dinner-dance given by Ronald Ferguson, the bride's father. Today she'll meet with Prime Minister Margaret Thatcher and tonight be guest of honor at a dinner the Prices are giving.

Tomorrow she'll go to the wedding and the wedding luncheon afterward at Buckingham Palace. Tomorrow night she's due at a dinner given by Lady Elizabeth Anson at Claridges.

Thursday morning, after paying a visit to the American Embassy, she'll fly back to Washington.

Their last Washington visit, this spring, had been a disaster. President Reagan provided an Oval Office welcome but Nancy Reagan was nowhere to be seen. "I am insulted," said Wanda Toscanini Horowitz, according to a Time magazine report then.

"She's temperamental," explained her husband, Vladimir Horowitz. "Toscanini, you know."

"I wish there were something I could do to change your mood for the better," USIA Director Charles Z. Wick, who had arranged the visit, told Wanda, who had expected to meet both Reagans before going off to the Soviet Union, Vladimir's first visit in 60 years.

There was, Wanda told him. Send her back to New York immediately.

Wick didn't, instead taking the Horowitzes home to Rock Creek Park, where Vladimir played Wick's own concert grand ("Boy, it's pretty good," the pianist pronounced) and Wanda admired Mary Jane Wick's orchids. Mollified when they learned that Nancy Reagan asked the Wicks to invite them back, the Horowitzes accepted.

*They're coming this weekend. Sunday night the Wicks are giving a dinner for them at the Ritz-Carlton. The next day both Reagans will receive them at the White House.

"It was a total misunderstanding," said Wick of that other visit. "The president receives people in the Oval Office and normally Mrs. Reagan is not there."

This time, who knows, the Horowitzes may even get beyond the Oval Office.

A best seller it is not. Yet.

But "The American Hostage: To Be or Not to Be" could be one of summer's sleepers for Americans going abroad, whatever their destination or purpose.

There are 39 pages of basic travel safety tips, like avoiding taxi lines at hotels, varying locations where you flag a cab, watching to see if the same driver picks you up every day. And some not so basic: picking a code word by which your family can confirm your identity or condition; leaving behind with your family a tape recording of your voice; learning to detect foot, vehicular and fixed surveillance techniques by would-be captors.

There also are suggestions on what to listen for, smell and touch if you're blindfolded, how to leave a trail that somebody might recognize, how to behave if you're stuck in a black cell with only your mind to keep you company.

Written by security experts who learned their trade at the State Department, the Secret Service, Central Intelligence Agency and Department of the Army and who spent a total of 85 years "travelling, living and surviving on all continents," the book boils down to pure and simple survival.

"Survival before, during and after the fact of becoming a hostage," say the authors, who include Richard Keiser, formerly with the Secret Service as head of presidents Nixon's, Ford's and Carter's protective details; Herbert F. Saunders, a former senior official of the CIA; and William J. Mulligan, who spent 27 years abroad for the State Department.

The book is available for $9.50 through Varicon International of Falls Church, a 13-month-old firm of security consultants.