You would dclick the pet release deed then on a pet of yours turning the pet invulnerable (yellow) like a npc. The pet would stay in the range of..... say the yard wand which would be 10 tiles of your house. This would be mearly for deco purposes. Once you would release the pet it could not be turned back. Just thought it would be cool to deco ones yard with some live animals.....
I like this idea, although some creatures might not work so well for it--basically, hostile tamables or unicorns. Perhaps if the deed also altered the behavior so that they became about as aggressive as a horse (aka passive)? Otherwise, people might be in for nasty surprises when they visited houses...