The jerk boundary: jerk boundaries are boundaries that are reasonable in some contexts but not others.
Let me explain.
Mummy can tell little Johnny that smearing jam on the wall or picking Mrs Henderson's zinnias is 'not OK', because Johnny has not (yet) developed a moral compass and needs to be taught right from wrong.
Bosses, teachers, and even sponsors will need to do some explaining to employees, students, and even sponsees of 'how things are done round here' (or 'how things are done generally'). Bosses and teachers have natural authority by virtue of their position; sponsors are chosen to have that authority. Pointing out breaches of etiquette is fine. Pointing out actual acting out is fine.
But with all other relationships, there's a helpful way and and unhelpful way to set boundaries.
The unhelpful way: telling someone that something's 'not OK'. The implication is that the 'not OK-ness' is a breach of a universally recognised norm that the perpetrator is unaware of and needs to be educated about, and the boundary-setter is the appointed emissary from the Kingdom of Moral Truth: superior, hypervigilant, and chiding.
It's presumptuous, patronising, and makes normal relationships impossible. The perpetrator is cast as the errant, ignorant, and barbarous child that needs to be sewn up in the educator's moral corset, for everyone's good. You can't have a relationship with someone when that's the role you're assigned.
What's the alternative?
There are two, actually.
There's the very neutral situational 'no'. 'No' doesn't mean 'never' or 'no one'; it just means 'not right here, not right now.'
Then there's the more overt, 'Could I request that you don't ...?' or 'Could you possibly ...?' or the 'It would really help me out if you could ...?', etc., plus an explanation, if asked for.
The request is not justified by implicit reference to a universal standard.
It is simply part of an exchange where two people are trying to muddle through together. There's no judgement; no right or wrong. Just negotiation.