The TRAVELER'S JOURNAL: March twenty-first, wondering whether it's the guilt in their eyes or the heft in their handbags?

For most incoming travelers, clearing customs involves a passport check and filing a declaration of goods acquired abroad. Once every 30 days, each returning adult resident out of the U.S. for at least 48 hours can bring back $400 worth of goods duty- free.

That basic rule applies to most merchandise from most other countries, but there are specific exceptions, especially on tobacco and alcohol. In general, all items over the limit, whether bought or received as a gift, must be declared, and appropriate duty paid. If asked, travelers must be able to produce a sales receipt showing a reasonable purchase price for any item listed. If they can't, a value will be assigned and appropriate duty collected.

Some major airports have a so- called Quick Look system. Instead of standing in long lines, travelers who have nothing to declare can pass through a green aisle, subject to only random checks. When fishing for amateur smugglers, customs inspectors are alert for tip-offs like suspiciously round numbers on a declaration form or totals falling just under the duty-free limit.

However, they're more concerned with gross offenders and also try to gauge a traveler's affluence by dress, luggage and attitude. When casually questioned, people who are trying to sneak in something without paying duty often become resentful or anxious. Other clues include women who turn their backs when opening their handbags and men who back off to the side to let their wives explain the declarations forms.