I live in a townhouse community too and have the same box. I currently unplug my UMC each day and store it in my trunk. I only plan to be living here another year or two, so hopefully the box will last long enough.
I've been thinking about how best to rig up some sort of locking solution. I may try to jury-rig something with a Kensington cable lock for a laptop. If I come up with something, I'll let you know.