I've stopped tagging accounts, since last month's incident. but if I'm allowed to tag them, then I can do it.
Also,my assumption is that the activity patterns on the above accounts are the same person.
If you don't flag the cheaters you catch, what's the point of doing this at all. What are we changing? We know that they are cheating, but it does not reflect on them in any way. Thus, we give the go-ahead for all other participants to increase and participate with alternative accounts where it is prohibited.
Where did you get the idea that you are not allowed to post negative tags? If you have hard evidence, I think you should tag all cheaters.