Reinventing the wheel(ed rules)

Here's an interesting manager issue I had lately:

We have a lot of people who are homeless who use our library and some of them take their stuff around the neighborhood in stolen shopping carts. We have a problem with people leaving their carts right by the front door so that they are in line of sight from inside the building. I get why people want to do that, but it blocks the front doors, and there's a risk of them running into the parking lot RIGHT by where our book drop is and colliding with someone's car. For this story, it's also important to note that our library has a handful of bike locks that we lend to patrons so they can lock their bikes to our bike rack outside if they don't have their own lock.

Me in a staff meeting yesterday: Anyone noticing any patterns of issues with the building?
Same coworker who wanted to know if I wanted to see 'something related to the building which will make you feel stressed and discouraged': I've noticed a lot of people leaving shopping carts by the front door lately.
Me: Yeah, that's a problem. Please keep moving them out of the way.
Coworker: But where should we put them?
Me: I guess by the bike rack? Since that's where we have people put bikes and scooters and anything else with wheels?
Coworker: People don't like putting their bikes there because they can't see it from inside. I bet the same think will happen with the shopping carts...if someone asks me for a bike lock to lock their shopping cart to the bike rack, what should I say?
Me: Give it to them.
Coworker: But those carts are technically stolen, right? That's illegal!
Me: [Coworker], pick your battles.