To have that for pets is a very nice idea, I think. It wouldn't require a lot of effort from the devs/GMs to train them as the owner would do it. GMs however would require a way to review the pet personality and/or a command to reset it if someone really screwed it up.
I'd love to see that! ...and I *think* that's a bit simpler to do then watch out for all the NPCs what they're learning from random people. ...ye gods! *I* know I wouldn't want some of them to repeat what I've told them after a quest I did broke or got seriously stuck in it.
That's what I meant with
But there the effort there can be minimised (following Alan's example) by giving the player the option to save the chatlog with the chatterbot/NPC and simply having a dev (I volunteer Clap ) reviewing the logs and correcting the behaviour.
A chatterbot-NPC would ask "do you really want me to remember what you just told me?" [yes/no] at the end of a conversation.
If you choose [yes], your log gets saved and is opened for reviewal, otherwise it doesn't affect the NPC.