There was a post on /r/legaladvice where someone's neighbor sold a plot of land, causing them to effectively be landlocked, but there was a road through OP's land connected to the seller's property with a locked gate to which the seller was demanding access. Basically everyone was telling OP not to allow the seller access, even once, as that would set a precedent.
I was raging reading this /r/legaladvice saga. That's just an incredibly great story about a chunk of land. Thanks for linking to it!