It's an unwritten rule among fitness pros that one should never "correct" another in front of a client. Egos are tweaked, glares are exchanged, and the relationship between colleagues can quickly head south.
That's tough, however, for trainers with more experience who may witness a green trainer doing something unwise or potentially dangerous with a client. The seasoned trainer, I believe, has the moral obligation to speak up. And the less experienced trainer would do well to listen without getting feathers ruffled. If we are thinking of the client first - and if we can all admit that none of us are perfect - then it serves everyone involved to accept tips, suggestions and even corrections, when they’re given with helpful intentions. Remember, the client just wants a safe, effective and enjoyable workout and probably feels even more special to have two trainers working toward that goal.