Ask the rmt. Normally short underwear helps them to work. Full naked sometimes hard for them to keep the drape secure. You normally can ask them, how they prefer short underwear or naked’. Though they can drape you in any way.
It’s better to ask receipt before booking anywhere if receipt matters to you. Now most of the therapists Mentioning Rmt & receipts (even if they can’t provide) because kijiji otherwise not allowing ads.