Whenever I go to get a massage, and this is at a respectable place, not the shady happy ending massage places, they always have a sheet or blanket covering me, and shift the blanket accordingly throughout the massage. I am completely fine with myself being exposed, so is it ok if I tell them to do it without the sheet? Is it used to 'protect' the masseuse from liability or something? Is it to 'protect' me the client from anything? What's common practice in a situation like this?