Re: Neighbor's Basketball Court / Encroachment
Are you sure the asphalt is on your property? It seems very presumptuous of a person to actually lay asphalt on property that isn't theirs.
Yes, you do have liability issues and giving them permissive use makes it worse. You have a greater duty to an invitee than you do a trespasser.
Even if you do get the neighbors to waive any claims, that won't apply to people not signing the same waiver. Beyond that, the enforceability of a waiver is something a court would have to determine. That means, unless them signing it keeps them from suing, you would still have to defend yourself in court, and there is a possibility of you losing, depending on the circumstances.
I am not an attorney and any advice is not to be construed as legal advice. You might even want to ignore my advice. Actually, there are plenty of real attorneys that you might want to ignore as well.