I can understand why advance notice is requested for the professional companion. Shit happens .. pardon the pun. On the other hand, in the heat of the moment things happrn in RL but then thats real life not a fantasy your paying for.
I think my favorite experience was with my ATF and I explained I had never done greek... she laughed.. shifted around a bit and triumphanly procliamed... now you have!... fun stuff.
But yes, only fair if you want greek that its known ahead of time... just like in the movies, girls need time or you had better be ok with unintentional.... extras.