I see this type of thing consistently, players rated 200+ points under the tournament limit (u1600 in my case) who consistently place in the top 5 in said tournaments, often dominating them with 100% or near-100% win rates against much higher rated competitors. In the average tournament I have played in I would say that usually 2 or more of the top 5 finishers fit this description. Clearly the odds of this happening without sandbagging or other forms of cheating are virtually zero, yet there seems to be no program in place to effectively counteract it.
I have reported a number of these cases to the cheats room, and also via email to email@example.com, usually with no response whatsoever. I think it is fair to ask that obvious cases of sandbagging be dealt with in an effective manner, as to not do so gives a significant edge to cheaters, and can only serve to demoralize those who wish to play fairly (or conceivably lead them towards sandbagging themselves - a domino effect of sorts).
I have mentioned this suggestion elsewhere, but perhaps the average rating of those playing in unrated tournaments could be calculated (by their results in said tournaments) every 3-4 weeks, and their rating adjusted accordingly at that time. Those seen to be deliberately sandbagging to influence those results (for example, dominating one tourney then deliberately losing most games in others to fool the system) could be warned, and suspended/banned after multiple infractions.
I imagine there is some mathematical formula that could be used to flag suspected sandbaggers for review (both currently and under my proposed change above), as the extreme cases are already pretty clear to anyone with basic chess and/or statistical knowledge. I realize that some degree of sandbagging will always take place in any venture in which lower rated players get bonuses (extra time in this case), but I also think that improvements can be made.
It seems clear to me that leaving sandbagging virtually undealt with is very likely to lead to loss in moral and faith of this site by its members (and prospective members, as few people want to utilize - and especially not pay for - a service in which significant levels of fraud is endemic).
I request that an administrator address the concerns listed above in a reply below, as this is a matter of genuine concern to myself and others here, and a matter of basic fairness and integrity which should be fundamental to any legitimate service.