I must admit I like the idea of demos though. Really gives you some hands on before you make your buying decision.
I think people realise that its not truely indicative of the full game experience either, just lets the masses know it'll run on their rig for sure etc.
Besides a solid sale is a solid sale! then maybe less of this 'return it after install and get your money back' lark.... it can't be too good for the industry!
oh and I thought UT2K4 demo was alright.... let me taste Onslaught

now I'm hooked.... oh and that was what made the decision to buy it too hehe.