Bike Lock Removed from Bike Rack

It was fun, not really, to discover this morning that my bike lock was removed from the bike rack in front of the building where I work (Clark & Jackson).

I have been storing my lock on the rack for the past three years without a problem.   There have been other locks stored on the rack.   All of the locks were removed when I went to lock my bike today.

I asked someone in the building and they said that the city would have removed the locks.  Is this a practice by the city?   Is their a rule against keeping locks on the bike racks?

This is the firts that I cave come across this.

Thanks.