They're doing that. Original account gets a few months when they're found out, DA gets permabanned - usually without fanfare. Mods never answers questions as to which ones it was.
As for "everyone", I'm sure someone here are enjoying themselves with more accounts and enough computer-savvy not to get caught doing it, but the large majority will settle for one account only. You are certainly in the running for LLTHADA.
I blew my chance at making a double account when I decided to log in here from work.
Now they have both home and work IP addresses attached to my posts. I'm not tech-savvy enough for any of that other stuff. (also, I have a life so I can't be arsed to spend time on it