"While at a service station in Bethesda," writes a resident of that area, "I was approached by a young man on crutches. His leg was in a cast.

"He explained that he had just had his broken leg set and that he needed $5 to get a prescription filled for pain-killer. He'd pay me back as soon as he got home.

"He gave me his name, address and phone number, I gave him mine, and I gave him $5. When I got home and told my wife about the incident, she told me that you had been writing about scams of various kinds. We dialed the number the young fellow had given me. It was not in service.I'm embarrassed enough about being played for a sucker to ask that you not publish my name."

There is nothing for you to be embarrassed about, sir. The person who ought to be embarrassed is the one who thinks it is clever to live off people who respond to what purport to be genuine appeals for help.

His breed has now grown so numerous that even warmhearted people have become wary of pleas for aid. Quite often, people who are genuinely in need are turned away because Mr. Nice Guy has been fleeced so often he has become suspicious of all requests for help.

When the choice is between the risk of being cheated by a con artist and the risk of turning away a person who really needs help, Mr. Nice Guy ought to ponder his options before he says "No."

This fellow who says his name is John Smith of Silver Spring -- does he carry a driver's license? A letter addressed to him? Any other ID? Do his name, address and phone number check out in the phone book? Which doctor put the cast on his leg? At which hospital? How is this guy on crutches going to get to a drug-store? Can you drive him there and pay for the prescription?

Similar questions can be put to the scoundrel who says gasoline was siphoned out of his tank. Surely, his car must be nearby. Will he show it to you? Does it have a license number? Where is his driver's license? It is illegal to drive a car without having both a driver's license and registration card in your possession.

In short, Mr. Nice Guy must try to find out whether the person seeking help can produce some corroboration for his story.

If the stranger becomes impatient with your questions or becomes indignant at your lack of trust in him, he will leave in a huff.

When that happens, smile silently. He was playing a game with you -- and this time he lost. UPDATE

Incidentally, be aware that women are now turning to con games in greater numbers, and their victims are often women.

Dr. Regina O. Hughes was outside the Museum of Natural History recently when a middle-aged woman in a pantsuit came up to her and exclaimed, "Oh, what a beautiful dress you are wearing." Meanwhile she attempted to kiss Dr. Hughes.

Then the woman in the pantsuit began to weep. She said her husband was sick with cancer at Georgetown University Hospital and she was walking there because she had no bus fare. Dr. Hughes gave her money for bus fare, and again the woman attempted to kiss her. Later, Dr. Hughes realized that a year ago, at 12th and F, the same woman asked her for bus fare to visit her husband. On that occasion, the husband was in George Washington University Hospital awaiting heart surgery. The opening line then had also been, "Oh, what a beautiful dress you're wearing," and the woman had also attempted to kiss Dr. Hughes.

My guess is that the kissing bit was almost certainly a cover for an attempt to pick the victim's pocket or remove her wallet from her purse.

In this regard, I think supermarkets and other stores would do a great service to their customers by posting signs reminding them to guard their pocketbooks and to beware of jostling.

Whether they work alone or in pairs, pickpockets very often jostle their victims to distract attention at the moment the theft occurs. In recent days I have had many reports from older women who have been jostled by other women at the grocery store and then discovered that their Social Security checks had been stolen from their purses.

Stealing a widow's Social Security check is about as low as a thief can get, but it happens with distressing frequency. If you have a friend or relative who is in danger of being victimized, please warn her to be careful, and give her an occasional reminder.

The best insurance against losing a Social Security check is "Direct Deposit." The government's computer talks to the bank's computer, and funds are transferred electronically to each pensioner's account. No mail delays, no thefts.