Just block P2P access on Government computers and leave the rest of us alone. There. Problem solved.
Working in a .gov facility and being partially responsible for security I can VERIFY personally that these things are:
A) Against policy
B) Not allowed through on the firwall
C) We scan for it
D) Traffic get’s inspected looking for signatures
Bigger problems we are having is for instance with MSN Messenger due to some hearing impaired employees utilizing it.
Also, thumbdrives are a problem since there are legitimate uses for them...