It is supposed to be considered as spam and all the conversations created by the shills should be deleted and I am also agrees that there should be a rule against such kind of behavior because bumping threads using incentives is against the rule so the thread will be immediately trashed but if they are using the account bumpers and paying out which is clearly visible but still there is no action.
Problem here is that you have to provide some proof that those altcoin projects are indeed paying those sock puppet accounts. So literally you would have to find something like this on their website in order to get ANN deleted (this was an airdrop case though, but it resulted in ann getting deleted). That kind of evidence unfortunately you wont find from those that hired bumping service. 
You can connect as much account as you want to as many threads, and it still won't be enough to get ANN deleted, as visible from sheet I made some time ago for that purpose. At least 17 accounts consistently working on at least 14 different threads (there were probably more threads but this was enough to make a point) simply can't be coincidence. So yeah, all you can do really until (if) rules change is to report single posts and thats about it.
