That may sound like a good idea, but has a big flaw:

Yes, we know then who is what role, BUT the mafia member knows this also. So, if I turn out to be the insane cop, the mafia member will then kill the real cop and it's pure guesswork and luck on the last day. The same happens if I am the cop (he would then kill the insande cop). Either way the only people left would be paranoid, naive and the mafia.

We should rather scry in a cycle:

Easyname -> Freshmeat_ -> PainintheEar -> Shadowcaller -> Yspoch -> Easyname

Yes I know, somewhere in this line the chain is broken by the mafia, but at least we will definatly gather some information, regardless of who is lynched and killed. And we "decide" what person the mafia member "scries" (and therefore lies about), which should hamper him quite a bit in his flexibility.

What do you think?