Sidewalk vendors deserve and usually get -- my absolute sympathy. But not lately -- not since I found out what's going on down at 18th and G Streets NW.

A man who passes by that corner daily called to tell me that two vendors were not bending the rules down there; they were breaking them. So I cruised by one afternoon to have a look.

Sure enough, two vendors were vending up a storm on the sidewalk, as the law allows. But each vendor had parked a supply vehicle in a one-hour-only metered space right beside his stand -- and that the law doesn't allow.

Of course, to park a supply vehicle right beside his vending stand is a tremendous convenience for the vendor. If he needs to get a few more enchiladas out of the truck, he doesn't have to walk five blocks to fetch them.

But as Isaac Newton might have said if he'd been a vendor (or a D.C. cop, or a D.C. columnist), for every convenience, there is an equal and opposite inconvenience. In this case, motorists who want to park in one of the more cluttered parts of town have two fewer spaces in which to do it.

So, cut it out, please, vendors. And how about a few nudging reminders, D.C. police?