About sums it up. Never thought about the ID / cash different pocket thing but it makes sense. Also, do your homework - that's the advantage of the iTrader feedback mechanism.
Just to reiterate. I'm the buyer and the seller is someone here on INGO.
So it's safer to bring a buddy along.
Public place
Get there early
Keep your ID and cash in a different pocket out of your wallet.
After transaction, just leave, don't linger
Of course, check the gun before closing the deal