"As I opened my wallet, I considered whether I should risk using this fake ID on the Secret Service. It probably amounted to a real crime."
I don't know if it amounts to a crime or not, but an SS agent is a federal agent, and I would think something like this could be construed as obstructing justice, even if no crime had actually been committed with respect to the $2 bills. Unlike their Nazi namesakes, the SS are fairly non-intrusive.
Nevertheless, Woz is an idiot. I'd have handed the agent some of the bills and said, "They're legit, purchased from the Department of the Treasury in sheets," though perfing them might fall into the category of "defacing," which is intended to cut down on these sorts of misunderstandings.
Yes, you can buy sheets of $2.
See here. Their intended purpose is for framing, not for being a jerk in Vegas. If you want a cut stack of 20 $2 bills, just ask your bank. If they can't get them, then you can buy them
here.
The article mentions something about printing them off on a die-sublimation printer, and that's a definite no-no.