Ok... when I'm out and about with the intention to perform magic, I normally carry 2 gaff decks with me. One is a one way forcing deck, and one is "Astral Projection"
What I fnd the best thing to do is, do a load of ungimmicked stuff with a normal deck (people have tried to "inspect" my normal deck before. Wtf?

) however, I then let them inspect it and they are satisfied.
Then, as I'm drawing to a close I'll say "Right thats about me done..." and put my deck away in one of my inside jacket pockets, or one of my combat trousers pockets. Then, as an afterthought, 'll say "Oh hang on... there is one other thing I could show you... I think you'll like it" and take out the gaffed deck. because spectators on the whole don't know what a gaffed deck is, (obviously they'd guess if they saw it...) and they assume the deck you take out of your pocket is the one you just put there... you can easily get away with it. they've already inspected it, and are unlikely to ask to see it again
Bizzarely... I did a few sleight of hand tricks on the bus using a red deck, and then pulled out my Astral Projection deck (which, D'oh! was a blue deck!!). Never mind thinks I, and carries on. One spectator swore and said "No way! That's impossble!" and another said "Man he's good... I even checked that deck out earlier!". Ah don't you love it when speccies do all the hard work for you?

You wont find much better anywhere and it's nothing - a rigmarole with a few bits of paper and lots of spiel. That is Mentalism
Tony Corinda