We have 1, it is popular-more so as summer and holidays/xmas comes along.
They have to fill a record card out, it has all the contra indications and abit of a disclaimer.
We have time limits that the courses last for-as it needs to be used 3 times a week to notice a differance. We get all clients to sign and agree to the time limit and end date.
It isn't my salon so don't know about the legal side. Xx