drrich2
Contributor
I don't recommend that approach for reasons that have little to do with GUE (which I've had no training from) or even recreational diving specifically; the thinking applies when seeking any professional service, whether training, medical services, etc...
I understand you may see this as heading off trouble, but it may cause it. A professional who is the sort of abrasive 'butthole' you wish to avoid might indeed get ticked and end things before they get started, but most instructors probably are not that type, and there's a cost to be paid in making a bad impression.
Most of us don't meet a physician, nurse, coach, instructor or other professional services provider for the first time and open with a statement demonstrating we believe rude, unprofessional behavior by them is sufficiently likely the possibility should be anticipated and addressed before there's any evidence of it. A limit-setting statement prior to any offense gives the impression you've had negative input about the profession and are guarded against it, may be a bit entitled and paranoid, and are prone to interpret ill intent.
In other words, it sends the message 'I've heard bad things about you people and I feel threatened by and guarded toward you.' You wrote:
A fair paraphrase might be 'I'm putting you on notice up front before I get to know you that I don't trust you and will not take your crap.' (It also conveys the impression people on SB trash-talk GUE, poisoning students against them at the start).
A good professional may conceal his eye roll and sigh, and present a positive, respectful, professionally reassuring manner, but still have a negative internal reaction to you (and ScubaBoard).
It's customary to give people the benefit of the doubt until they forfeit it through misbehavior. Some people travel far and pay significant money for GUE training, so exchanging some e-mails and listening to word-of-mouth from former students seems wise.
