Cantsay already mentioned, there was a similar case involving a member named nhaila last year
Thank you for highlighting it. Is it safe to conclude as far as is known, these two are the only two known cases of this type?It might slip under the radar for a week or two (unless the manager catches on earlier), but I highly doubt it can remain unnoticed for an extended period. The forum has a vigilant community with many observant members. 
The cheater in this case benefited from the fact that the spreadsheet for a particular campaign was kept hidden from the public.
Even if it slips under the radar it seems as though the vigilance of members (as you aptly refer to it) managed to spot it. At least he did not manage to carry on the duplicitous conduct for a considerable length of time and instead was caught out quite early on.The cheater in this case benefited from the fact that the spreadsheet for a particular campaign was kept hidden from the public.
Now he will have to create or buy another account and then go through the process of trying to rank up before being considered for joining signature campaigns.