A mystery at the Diesel

A well-dressed man took his cookie and coffee to the bar just now. After setting down the victuals and spreading his jacket on the stool, he reached under the bar surface (for there is a foot or so of overhang) and swiped his hand back and forth. He did this with the absentminded air of habit.

What purpose did this serve? Was he making sure that there wasn't any gum or boogers or something underneath, threatening his nice pants? But if that was the case, why was he willing to risk sticking his hand into it?

BTW I dropped down to a free account a little while ago and lost the use of most of my icons. I can't justify spending money on a full account right now. (I can, apparently, justify late-night border-crossing expensive-bagel missions, but that's different, since I had a partner in crime.)