Hmm, how about a neighboring business then? Wonder if they know that they were closed that day. Perhaps asked to get their mail and packages while they were out. At this point I would sit and think of any possible scenarios that could help me and go out to confirm them. Go do some Colombo stuff. Be prepared for the last chance meeting. 21 years is a long time to throw a driver out for 1 infraction. I really can't wrap my head around this one.