When you set boundaries from the onset, you communicate that you seek an outcome with a specific person—the opposite of the outcome independence you are supposed to embody. If you did not, you would take a step back and observe and assess relaxingly.
Boundaries are less about communicating them to others but more about knowing what yours are for yourself.
And that is why a lot of guys are getting it wrong with women.
When you are explicit in your boundaries off the bat, it is like girls' shit tests. It is gross and uncouth.
A poor show of power posturing to better show one does not have any.
Accurate testing and qualifying are subtle.
Warnings with women rarely work; you are only fooling yourself that you have more control than you do. Or even you comfort yourself that you will leave in a said situation. If you need to say it, it is more to convince yourself than to warn the other person.
When you are comfortable with yourself and what is acceptable in others, you show two things by stating boundaries off the bat: