4. (a) That's not right. In an action for trespass to land, the plaintiff does not need to prove any actual harm, damage or loss as a result of the defendant's intrusion. If damage does result from the trespass, the plaintiff can claim compensatory damages. Otherwise, a declaration of rights may provide sufficient relief, establishing the plaintiff's legal rights beyond further dispute. A court order called an 'injunction' can also be sought to prevent further intrusions.

Note that an occupier of land also has the right to use reasonable force to eject a trespasser. But the trespasser should first be given an opportunity to leave voluntarily.