I think all this weird creepiness with IOS 4.2 beta expiring is due to it being Halloween.
On a serious note though, I'm kinda concerned because I'm on vacation in OZ and heading back to PNG (where there is no broadband) and if the beta expires while I'm there I have no where to download a later beta or full 4.2 once it comes out.
Beta 3 has been perfect for 2 weeks and I could definitely use it just fine until 4.2 comes out and someone downloads and sends it to me by flash drive.