The issue here is not should flight crew be screened, it is that most other people associated with the operation of aircraft are not. If you are going to screen one group you need to screen the lot and that means the cleaners, catering, the aircraft washers, engineers and the safety officers, cutter 1, and the guy to dumps the loo...and the list goes on.
As for us (pilots), do like they do in Adelaide and provide a dedicated screening point for crew and ground staff only...just outside our crew room away from the public screening point. Everyone including ground staff and engineers who go airside are screened there and that is how it should be.
I read a few weeks ago about the USA trailing a more stream lined proceedure for flight crew only which enables them to proceed through security in a matter of seconds.