Do they respect your husband who loves you? I agree with a lock on the gate in general, not just for your husbands bil and friends but any person like a mailman could open the gate and leave it swinging in the wind. Let thus one pass and find some excuse to lock the gate based on someone other than them leaving the gate open. Or put the respect issue onto your husband, if they don't respect you and your dog they are not respecting him as well. Lol, you could always tell him it's time to move again to a more secure and safe location. Or just put a lock on the gate. Best of luck.