We buried two dogs at our old house, and told the new owners exactly where we buried them. Both dogs had rose bushes planted over their burial sites, which the new owners promptly ripped out, along with the rest of the garden we spent years cultivating. If they come across Copper's or Rufus' remains that's entirely their own fault. Both that house and our current house were built in the 1930s, so there's a chance that either or both gardens have previous owners' pets buried in the gardens as well. Our current garden has one of our cats buried in it (we've also buried four pet rats, but I doubt there's much of them left by now). At my parents' old house in Toronto, however, we weren't allowed to bury our dog. She had to be cremated.