I say...invite them in! Have a party!

LOL sorry, I couldn't help myself.

I think it is definately a personal decision. If you can afford the other place, go for it! If not, get after the managment at your apartment complex...ask for gates, security cameras, a night at least once at night. Call the police out every single time, and the police will get annoyed and maybe talk to management. Or the homeless people might get a clue and find somewhere else to go.