Sometimes it is hard to tell where the line is.
For example,
@Deep Six gear. I am a big fan of the company and what they are doing, and I try to advocate support for them wherever I can. Because of their business model, if a customer uses my reference code, they get a discount on purchases. I also get a commission on EVERY purchase they make after that, as the referring instructor.
Now, I had to decide whether to put my referral link in my signature line or paste it into posts when referring people to the site. I chose not to for the reasons John has described up top. I also loaned a set to a diver here that has nothing to do with them and was skeptical. I encouraged him to write up a honest review of the regs which he did.
I know that I would refer them anyway, I wouldn't have an account if I didn't, but since no-one is in my head there is always the possibility of misinterpretation. By removing that link, I now have nothing to gain from a referral so hopefully that will un-muddy the waters.
That being said, is it possible that at some future date I might get an extra coffee mug or T-shirt from Chris in an order as a thank you for my support? Maybe.
Would that be wrong? I don't think so but I can definitely see where some may perceive that as coloring my views.
I believe that an upfront disclosure is valuable, I also don't believe that it is our job as mods to go play detective to see whether someone is on the level. Obvious cases of misrepresentation, sure, but trying to find out if Bob and Fred have a financial arrangement is way outside my pay-grade as a mod.