My office used to be in downtown Minneapolis and one of the guys I worked with used to use those bus racks.
One day he put his bike on the rack and hopped on the bus as usual, but when he got to his stop downtown his bike was gone.
He said he figured that someone got off the bus on one of the stops before his and just helped themselves to his bike. /img/vbsmilies/smilies/frown.gif