People will be able to discern who is who based on avatars, merit count, merit history, signature, rank, and probably other things. The point is a random username won't do much if people can still find out who is who IMO. You would need to randomize everything.
I noticed this when I read the OP, the total merit and activity make it pretty obvious who this anonymous account might be. I think it’s worth considering if there’s a script that could hide those details.
Actually, I like the idea OP presented because, personally, I’ve observed this could indeed be the case. Bias is always present, especially if you know the user either from this forum or if both of you are part of a group or community outside the forum.