This trick will not work with the current version of New York licenses (although you may be able to
change your grip to obfuscate the issues but that wouldn't be very clean). You can do this with bank
cards and the like, but then you miss the whole point.
I also don't like the handling
much. You have to fiddle with the envelopes in a suspicious way that has nothing to do with the
method but does not look clean. For this effect to sell it has to really look clean. You probably
could do it with your head turned or something like that during the suspicious part but that was
never mentioned during the instructions.
Long story short, there are better ways to do
this trick. Yes, they involve a minimal amount of arts and crafts but this trick isn't impromptu so
I see no reason not to spend two minutes making a much better version of this trick.