There's practically no way to know someone is going to mess up your address. You can't be liable for that. If you're living at a place (or spend a lot of time

There's practically no way to know someone is going to mess up your address. You can't be liable for that. If you're living at a place (or spend a lot of time there) you'd have seen the workers working at your place. Catching them mid job and letting them know right away wouldn't result in unjust enrichment. Letting someone build a whole house on your property while you knew about it would be unjust enrichment.