If you care about your campaign, maybe you should limit the criteria of Newbie accounts that apply. Even newly created accounts you accept, it's like you intentionally attract cheaters to participate in making your campaign successful.
This would not stop cheaters doing the same cheating like usual, they only need to upgrade to jr.member rank or get those accounts in some other way.If they are willing to do this kind of cheating for extra $5 than they can do much worse
I would not accept any inactive members, and I would take a look at forum history of all participants.
Also I don't disregard the fact that the pay is also an influence on this.
This is the lowest Chester's can go in my opinion because $5 is a kind of too low to get the attention pf any reputable forum members and only newbies and Jr. Members will take such offers seriously amd if you notice a trend in the suspected accounts you will see that their are alts and most are low ranks.
The fact is in this review reputable members here won't really matter simply because the review ought to be posted on playstore and so viewers might not even be aware or recognize those who are really reputable at Bitcointalk there, this makes them focusing on rep members not their top priority rather the more, the merrier.