Pathways.
Pick the door.

One interested client. Open the landing and pass the tablet over: they press Book, the form reveals, they submit. The reset link hands it to the next person.

Several interested at once. The screen becomes the studio invitation; every phone scans and books itself.

A participant wants to invite someone. Assign their code and copy the share link; if they've already left, the referral email carries the same link.

The walk-in names the friend who sent them. Type the friend's email: the register returns their code if they own one, or assigns a fresh one. Then pick the room you're in.

Either way the walk-in's form arrives with the CODE seated, and the friend becomes tomorrow's invitation.

The referral door closes gently and the client door opens: they join Path A or B above as a new client. Nobody is turned away, and no code is ever guessed.