We do, in fact, have an example of a user who participates in multiple campaigns with publicly-announced alternate accounts: hilariousandco, hilariousetc.
You forgot to add hilarious* u=1424594 is an alt of hilariousandco u=164822 and also has a confirmed second alt of hilariousetc u=397737
The problem you ultimately have with alts / known or otherwise is that they will eventually give each-other merits, or trust wall/feedback (or even default trust) and put themselves onto DT to get a higher payout from any campaigns they are posting in.
As we've seen once someone is on DT as hilarious is, they then use their only bargaining chip to slap others with distrust such as when I posted (the already known) information on his trust/feedback wall.