extremely context-dependent for me, depends a lot on what “reward” means and what my relationship is to the person. i think “don’t feed the trolls” is unobjectionable vs. “shower my partner with affection when she does things i like and ignore her otherwise” is emotional abuse
i think it should be "shower partner with affection when they do things you like" and "ignore when they do bad things" but not even like "cold shoulder," more like "they said rude thing, dont respond in the moment"
which may still be objectionable
there's additional nuances here around what you mean by "ignore." big difference between like "don't take her bait" vs. "completely stonewall her emotionally"
it's also uh cruel and imo people just shouldn't do it if they can avoid it :S like you could gloss it as neutral but in the context of an intimate relationship it can be a form of punishment if being used deliberately