However, if Farmer is found to have committed a battery, this might constitute a superseding cause relieving Joyce and Jimmy of liability.
Nuisance by Joyce and Jimmy: Farmer could sue Joyce and Jimmy on a nuisance theory, since they (in combination with other snowmobilers) substantially interfered with his use and enjoyment of his property. However, in view of his trespass claim, it is unlikely that Farmer would bother to assert the nuisance one.
Battery by Farmer: The use of the barriers by Farmer might be a battery against Jimmy and Joyce, if they can show that Farmer either intended to cause the contact with their bodies or snowmobile, or knew that such a contact was substantially certain to follow. In trying to prove this, Joyce and Jimmy will want to point to the fact that the outer barriers were covered up, which indicates that Farmer was trying to hurt snowmobilers, not merely keep them out. On the other hand, Farmer could show that the barrier that was crashed into was uncovered, and could claim that he was just trying to keep people off the trail once they got onto the property.
In any event, Farmer is certainly likely to assert that he was privileged to erect the barriers, to prevent trespass. To sustain this privilege, he will have to show that he used no greater degree of forced than seemed reasonably necessary, and that this force was not deadly (i.e., not likely to cause death or serious bodily injury). Since Farmer knew that most of the snowmobiling took place at night, on what are presumably unlit trails, the use of such barriers does seem likely to cause serious harm. If so, the case would be similar to Katko v. Briney, and there would be no privilege, since Farmer’s own safety, and the sanctity of his dwelling, were not in danger.
Even if Farmer succeeds in showing that the barrier should not be considered deadly force, he may lose his privilege by virtue of his failure to warn of the device’s existence.
Negligence by Farmer in erecting barrier: Even if the erection of the barrier is not a battery by Farmer, it might be negligence on his part, if it constituted a failure to use ordinary care. However, the duty of care owed by a landowner to trespassers is limited.
Jimmy and Joyce might be found to have been “constant trespassers on a limited area” (the trail), in which case Farmer would have at least a duty to warn them of dangers they were unlikely to discover for themselves, of which the barrier is probably an instance. Alternatively, if Jimmy and Joyce are children (the question does not indicate whether they are), Farmer might have a duty of care towards them, if he knew that many of the snowmobilers typically were children.
Even if Farmer were found to have been negligent, Jimmy might be held to have assumed the risk, or to have been contributorily negligent. These defenses are discussed in the treatment of his suit against Joyce, below.
Negligence by Joyce towards Jimmy: Joyce’s conduct in driving at high speeds was probably negligent as to Jimmy. However, she will be able to assert several defenses based on his own conduct. First, he may be held to have assumed the risk. Normally one assumes the risk only as to particular risks that one is aware of; however, in this instance, Jimmy might be held to have assumed the risk of unknown dangers, especially ones that are incident to a dangerous activity like snowmobiling in the dark. However, even if Jimmy assumed the risk of a barrier, he did not necessarily assume the risk that Joyce would drive at high speeds; this would be a question of fact, turning on whether she had driven fast on other occasions with him, giving him reason to know that she was likely to do so again.