I agree that you are setting a boundary for yourself in making your request to her.
With the paper throwing example, that's a boundary for yourself, - I will not tolerate having paper thrown at me.
I guess we cannot set boundaries for other adults, it's something someone does for themselves, and others respect that boundary or we don't have a relationship with them.
Sounds like your T really did hear you set that boundary, and it respectful both of your boundary, and you for setting it.