As a therapist and salon owner, I wouldn't ask my staff to do more than three a day, because I wouldn't want to do more than three a day. I think a spa type environment is different, because you go into that knowing what to expect.
Having said that, if they were happy to do more, I wouldn't stop them!!!
We do offer a large variety of treatments, and our massages tend to be aromatherapy based rather than deep tissue x