Bava Kamma 47: Eating Poison

What happens if someone brings property into someone else's private domain, without permission, then the homeowner is exempt from paying for any damage to that property. With all expected ramifications... Permission to be there makes a difference, but what if the owner didn't watch his property well? Also, if one brought produce I to another's domain and the homeowner's animal was injured - by slipping on the produce or by eating it, there are many questions regarding liability - and who is responsible for making sure that the animal didn't do damage to the produce) (or that the produce didn't harm the animal).