I think if people were angels everything you just said would be 100% accurate. But I think there's too many people that would either not post a review at all or post a biased review, which contributes nothing. However, I do agree with you from a marketing standpoint. Promo codes are really helpful in spreading your game around via word of mouth, but again an an objective review has to be made for this to work. In all reality, I'm not against promo codes. I actually think the potential good of them outweighs the potential bad of them. I'm just hopefully getting people to see there is a potential downside to promo codes for a dev.
As with anything, there is a downside which you brought up. But, promo codes are just one tool, and you can only give people the benefit of the doubt.
I don't think a "high" post count is the right way to go about things (for example I have less than 50 posts but I've been lurking since this site started), but the attachment thing is an awesome idea. Though in theory that would add more people just making accounts to get codes. So honestly maybe a 10 LEGIT post count would add the incentive to be able to get access to a certain forum to read the attachment (or something like that) just so there are people who would be more likely to write a review (devs don't ask for rave reviews, just honest ones to fix their apps/market them). I haven't seen a high occurrence of non-TA members nabbing codes, but maybe I'm not on when codes are posted
Just thought Id say that im relatively new to the forums, although I have checked out the new games section of touch Arcade for about a month now... I've just recently starting visiting the forums to see what people's takes were on specific new games (as paying $1 over and over for games can add up quick- especially if you dont like them)... Anyways- I'm not one for posting topics although I would leave feedback if I was to take a code. I say this because the suggestion for having a minimum amount of posts wouldnt be fair to everyone either. Besides people like me, why should a newbee get shafted for being new member? For that matter, someone could flood each topic just to get to said minimum anyway, and no one wants to sift thru crap posts. Long story short- there will always be bad apples who find ways around rules and etiquite... and my only suggestion would be asking for PM's for codes so that you have user names to hold accountable.