you don't need to sue someone personally to have an effect.
Discussion of the matter with the state AGs offices, and with the FTC, however, carries FAR more weight than that of a consumer, because you are the one being harmed most directly.
You also have the industry inside track, since you're doing it.
Finally, you have a stake in the game because if the practice went away you could sell SP and such without these problems.
I have found that there are three groups of dive-shop owners and operators in this regard:
1. Those who think the policies are grand and wonderful. They profit from it, and they like it.
2. Those who realize that its a two-edged sword and that they're dancing with the devil. They're just not sure which devil is worse - the one they have or the one they'd get by working to change things. They won't get involved because the devil you know is usually better than the one you don't, and the risk of being wrong is significant. A lot of dive shops are in this position.
3. Those who know what's going on is wrong. They're either unhappy with it but deal because its how they stay in business, or they're unhappy with it and try to steer business to other firms, trying to influence things that way.
The problem with the folks in camp (3) is that they can't get where they want to go from where they are. You have the media touting some manufacturers over others through what I've argued are possibly-biased tests, and there's no way to verify or account for that. You have the public who WANTS those products, and who WILL go where they have to in order to get them. You have the dealers who WILL cost-shift to stay competitive, which screws YOU, because what sometimes gets offered as a "comp" is training at a discount (or even "free"), which debases your training program's value.
The fix is to (1) convince the people in camp (2) that they'd be better off with an open marketplace, and for those in camp (3) and those who can be dragged along from (2) to apply pressure to fix it. You don't have to sue - that's the wonder of the government when it comes to anti-competitive issues, in that they tend to be interested all on their own. You just have to give them enough information for them to think they've got something they can run with. If they judge that they CAN, and that there IS a legal problem with it, it is their job to chase that all on their own and without your money being involved.
The case to make is that the consumer - and you - are being hurt by these practices, and that they constitute an anti-competitive effort. Frankly, from what I've seen I think its easy to make the case, but I'm not a lawyer nor do I work for the government. But what I can do is raise cain with those offices and officials, forward whatever I can get my hands on in terms of information, and in general be a "squeaky wheel."
You won't get the consumer to help you Mike, at least not in the way you want them to. You MIGHT get them to call the state AG's office (as I have) or the FTC (ditto), but you won't get them to "not" buy the product. They'll buy it all right, from the least expensive source, eschewing the local dealer - which hurts ALL OF YOU, regardless of which camp - 1, 2, or 3 - you're in.