I'm always freshly showered beforehand. Did have a masseuse ask one time if I wanted to use the shower. I thought...why not? I bet it would make her more comfortable knowing I just got out of the shower. So I showered again. I think it worked, she seemed pretty comfortable.
I always arrive fresh-out-the-shower... But if she'd be more comfortable and prefer that I visit her shower before proceeding, that's ai'ite with me. Hell, she can even lather me up if she wants to.
I am with the ask her to join me crowd. However if i have asked her to wear something i may just get in and out of the shower myself as i like the eye candy and the undressing part. Though i like to be undressed by the provider as well adds to the atmosphere more and makes it less business like.
I'd have no problem complying. I mean, it's not like its crazy for someone to ask that, considering... but if it's something the provider asks of all her clients, she should probably post it on her site or ad, so she doesn't catch anyone off guard or make them feel like they're being singled out.