I once had a bicycle stolen from the basement of an apartment complex. The apartment had a rule that all bicycles were to be stored in the "secure" basement and could not be brought into the buildings so I stored my bicycle in the basement. I came out for a ride one day and predictably, the bicycle lock was shattered on the floor.

Needless to say, I bought a new bicycle and started storing it on the balcony. The bottom line is that anything left in area that is open to all people in the community could easily be stolen. I think the case of a condo, you have to store in somewhere inside your unit.