Rent underground parking spots

In my building I know which parking spots are used and which aren't. Also, I know the concierge who can give me a list of unassigned spaces.

All I need to do is buy a $50 fob (the renter will reimburse me), then rent out the spaces at $100/mnth. However, there is a very small risk they will get towed. Should I do it?

Depends. If you seriously need the money to live, then you have my vote. But if you already have loads of cash in your bank and wanna stack more, then no.

What you are about to do is (i think) not legal... Then again, most is... Rich people are doing illegal stuff the whole day and get away with it. Do what you wanna, your choice.