Yep. I know this isn't quite the same example, but even if someone is choking in a restaurant, my dad (a doctor) has to be careful if he decides to help. If the person gets angry for whatfuckingever reason, or something goes even slightly wrong, my dad could be sued or even lose his license for practicing outside of a hospital and thus without legal authority.    I'd imagine there's some similarity for "impersonating" a PT and training someone without the proper licensing.