I have been caught short more than once when the racks were full. The last time was in Charleston, SC. The last bus of the night came along and the rack was full, had to ride the full 14 miles back to my hotel... turned out it was quicker than the bus anyway.

In towns like the one I live near, the buses only run on the half hour, so if the rack is full you are going to have a looooong wait. Folder would be my first option rather than depending on a rack on a regular basis.

Aaron