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.
Why don't they tell the forum who the multiple accounts are? It's like not telling the public who a criminal is..