I Still, don't think your reasoning is right; so yes he shouldn't get a warning he was wanting to get muted/banned; I belive that EVERYONE no matter what they done should get at least 1 warning.
Yes they should I would. Due they could just go to the owner and say he was not given a warning to just get you in trouble but the owner already knew he was going to break a rule as he already told pheonix he was going to dupe pheonix just told him you can't but you can try.