I've yet to hear of anyone just ringing up their Retreat Host and saying "hey, come draw me a bath."
However, we've been asked more than once if we'd like to have a bath drawn. It's been offered to be ready when we were to return from a long day, it's been offered for formal night, and it's been just an open offer.
If you don't like the sound of it, then don't ask for it and drive on, but it's most certainly something they are ready, willing, able, and glad to do.