The site did have a Non-disclosure guaranteed (basically, any kind of fetish and personal ID will not be shared, for both parties, without either ones consent or notice.)
So say you do tell them you could shrink yourself to a cm or two, that's still technically a personal secret, no one would share it, not without consent or face a contract break and a legal followup. Either jail or pay a huge fee. (Part of the reason why you use the site.)
So now your in front of your door, waiting for the guest to arrive. You've prepared food, beds for the guest and everything. It's your first time hiring prostitutes, and six of them too. So your a little antsy.
Then the door rings, you open it to reveal all 6 girls you hire. Apparently they found each other on the way and walked together, talking and being excited about tonight.
"Esto es tan emocionante! (This is so Exciting!)," Maria exclaimed, she balled her hands as she hops into your house, talking to Adriana.
"Lo sé, ¿verdad? (I know right?!), I've never tried it with other people." Adriana chimes in next, before realizing something as her eyes bulge in fear, "Oh crap, ugh, where's the bathroom?" You told her it's near the kitchen, white door to the left. She made a dashed for it.
"Hm, quite the fancy house for our wealthy clients." Melanie is next, tagging along behind her is Shanene, "Shanene, this place is pretty fancy for a suburban house, any thoughts?"
Shanene accidentally trips on something, and fall down on the floor. When Melanie tries picking her up, you realized Melanie's tits and Shanene's ass were harmoniously jiggling together, acting in unison as she picks her up.
"WOO! Here comes the party gal!!" A set of bouncy breast almost slams to your face, before being halted by Micheala, the self-proclaimed party girl. "Oops sorry, hey there's the kitchen!" She said unapologetically, dashing into the kitchen to check the closet for something, alcohol probably?
Finally the last person, Dallas steps in. "Sorry about her, my name's Dallas! First time hiring us?" An ice breaker of sorts, you answered yes.
"Take it easy, we can talk first before... Y'know. Or if you want we could do a pillow talk. Or whatever else you wanna do. Just as long as it's according to the sites rules."
Of course, even if the sites illegal they'd be at risk if either of them, clients and workers, are at harm. So they made you and them sign a bunch of stuff, read a bunch of rules and after that your set on doing anything with them.
It's weird in practice and theory. But whatever makes them sleep easier over their beds of money.
Right, now to shrink. Wanna lie to them or tell them the truth?