I've never been asked to leave. My MO is to simply lay on the table naked, no covering. 90% of the time, the Therapist doesn't say anything, she simply starts the massage. The other 10% is split between covering me up without saying anything or covering me up on the flip. Over the years doing this, I only had one therapist admonish me that its the law to have draping as she covered me up.
I will add, with a legit therapist, you typically pay when the work is done. So if one of them complained and had me leave, I wouldn't pay, I'd simply get dressed and leave. Which is why, I think most of them simply cover you up and not say anything. But for those 10% that drape me, I definitely don't try any of my tricks, I just let them massage me.
The other 90%? Well, that's a different story for another thread. . .