I have three standard replies, depending upon who I is asking.
1) For total strangers who just stop to ask, "NO".
2) For friends, "Im sorry, but the pond is for me and my son. Bass have a memory and after suffering the stress of being hooked, tend to not bite again for quite a while (and often, they never bite that type bait again). So allowing you to fish would mean my son's fishing experience would suffer."
3)Most often used, "No, sorry. The pond is currently being managed for big bass and that includes a lot of record keeping, and restricted fishing. So it does not need fishing pressure right now."