Petless conduct: increment when the player starts with a pet or tames a monster.

This conduct could be accidentally broken by the taming effect of a magic trap, which is problematic. One solution is to have magic traps pacify instead of tame if the player has the pet option turned off, but mixing options and gameplay like that seems like a bad idea. Worth noting that polyselfless is another example of a conduct that can be broken accidentally and is far more likely to happen. Note that xNetHack’s implementation of petless conduct just turns the charismatic magic trap effect into a pacification of adjacent monsters regardless of whether you’re petless or not.

Another issue is the guardian angel; it would be especially cruel to unexpectedly break the conduct on the final level of the game. xNetHack’s implementation prevents the angel from appearing if you still have petless conduct intact when arriving on Astral.