hard spectators

Hello I have been playing around with a omni deck recently, I 've tried several different patters (using it as an ending of an ACR, or just as a stand alone trick etc). But no matter how I present it or try to manage the audience, after the initial reaction has lowered a bit, 9 out of 10 times...

Sorry I'm not trying to be a hog this is my last question lol. When you're doing to here than there hand trick, when a trick is over what would you do if a spectator says let me see that deck?? Obviously I tried to write after the trick hide the duplicate card and stuff in my pocket in case...