I would not consider it sensible, an questionable if legal, that individual property owners have a right to decide who is allowed to transgress their property in order to pass to another property. I do not claim to know Belize law, but having developed property in the States, there are laws that prohibit property owners from not allowing others to reach their property. Laws permit one property owner from "land locking" another from his property by not allowing an easement to pass.
You keep saying that there are laws against traffic driving north. What government authority made those laws? If it is the San Pedro Town Consul, then I would think it is a Town Ordinance, and they could amend that as they choose. If it is another authority, then the Mayor and Town should have no say in the matter. Either way, I find it hard to accept that property owners would have a right to prohibit others from transgressing their property to reach another property. And, I would think it would be a loosing argument to suggest that, if that were the case, the property owners could decide who and who could not have that right.