Think about it:
Let's say you cross a barrier (could happen to everyone in BDSM - but we all know how to deal with such a mishap, restore the submissive's trust, and eventually continue, etc...).

She'll always have the liberty of calling the bodyguard/pimp outside and threw you out.

Is that BDSM?

PS The very title of your message is totally wrong. A sexual partner temporarly accepting an act of domination/humiliation done upon her(/him)self is not a sub. Being a sub requires much more than that. Learn more.