Why when you reserve a a parking spot (for trucks) do you guys not mark the spots so that the truckers do not have to move? When they have to move sometimes they are out of hours, tired, and weary....they have to go pay for their spot....then go move

First I've heard that spots were ever assigned.

I was told there's a 10 minute overlap in time. Eg. Someone reserves a spot online and at the same time someone pays for the same stop on site. It shouldn't happen but apparently it does. Sometimes it's also that drivers park in an 'empty' spot and then go inside to pay and don't move to the assigned spot after but remain where they are.