Likemany other Detroit area residents, I enjoy visiting Windsor, Ontario, for Chinese food. On Saturday mornings when I visit for dim sum, the Canadian border guards usually ask a few routine questions and occasionally make a friendly comment about the cuisine. Returning to my own country is sometimes a little different.

Just over a year ago, I was stopped by the U.S. Customs Service. I was in a car with two other Asian Americans. I also was with my girlfriend, who is white. After we were told that we would have to answer a few questions, we went inside an office and waited in line behind about 10 people, only two of whom seemed to be non-Hispanic whites.

Then each of us was asked where we were born and what we did for a living. I was asked a few more questions. The Customs Service wanted to know, for example, how I had met my girlfriend and how long we had known one another. The entire incident lasted a quarter of an hour; it was not anything terrible.

Afterward, though, I wondered who the Customs Service thought we were and what they thought we were doing. So I wrote to them.

A month later, I received a reply. They explained, "Contrary to belief, law enforcement officials, including Customs and Immigration inspectors, cannot distinguish between honorable, law-abiding citizens and violators on the basis of their physical appearance alone."

Of course, they are right. Indeed, that is just the point. You cannot tell the difference between the law-abiding and the possibly law-breaking simply by the way they happen to look. That is exactly why you shouldn't guess, especially when you might be focusing on race.

Other than race, I do not know what difference the Customs Service could find between me and my non-Asian friend. We have similar social and economic backgrounds. We speak the same language. We were even dressed similarly.

The letter continued, "Many attempts at alien smuggling are made by people posing to be friends to a 'non-suspect' traveler... . Even though the questions may seem irrelevant or out of place to you, there is a purpose for asking them."

The letter does not attempt to explain why I was suspect and my friend was not. Whatever the purpose of questions about the "authenticity" of relationships between nonwhite and whites, the same purpose should exist for asking two whites similar questions, if anyone should be asked at all.

Although I saved the letter, I forgot about this incident. Recent events, however, lead me to believe that I saw only a small part of a much larger problem. It is exemplified by the Customs Service approach, which tries to excuse or justify stereotyping as reasonable.

While we all carry around prejudices, stereotypes that are based on race and ethnicity are especially dangerous. Race and ethnicity, along with a few other traits, have been abused so much in the past that we should be wary of relying on them to prove anything. Even when our beliefs have a germ of truth, it is distorted and exaggerated.

Now with the Persian Gulf crisis, Arab Americans are facing discrimination. In Detroit, the metropolitan area with the largest concentration of Arab Americans, they are harassed with questioning at the airport beyond that directed at most of us. Nationally, the FBI is paying ambiguous visits to Arab Americans. The Immigration and Naturalization Service reportedly drew up plans in 1987 to quarantine Arab Americans in case of war with certain Arab nations.

Quarantine, with its vague scientific sound, would recall the Japanese-American experience during World War II. They were wrongly accused of being disloyal. Citizens were placed in "internment camps" not because the government had proved that any individual was guilty of collaboration or espionage, but because public sentiment condemned everyone with Japanese ancestry. As Lt. Gen. John L. DeWitt said, "A Jap's a Jap, and that's all there is to it."

The government has recently owned up to the shamefulness of the internment. Congress is issuing reparations to the individuals who were imprisoned.

Because of my own experience with having my citizenship questioned, I sympathize with Arab Americans. If each of us paused to remember history and our own feelings upon confronting discrimination, we would be able to avoid hysteria at home as war rages overseas. The writer is a law student at the University of Michigan.