Never trust any cage or anything like that, where other people have access. Theft does happen from those places so lock it up just as you would on the street and maybe better because anyone can gain access as someone could walk up and say oh man I left my key up in the office can you help me get in or they could already be in cahoots or just break in and guards generally don't care and even on places like Military bases and facilities things get stolen. If it can easily come off the bike without a tool take it with you or lock it really well.