My ex-roommates uncle is a former Narc and now does Airport security (in California). His uncle apparently said that it was totally legal to go through security with marijuana. Even if you don't have a card, it is very possible because requiring someone to disclose their medical history (ie asking if they have a prescription for the weed they're carrying) is a breach of privacy. As always, when dealing with the popos,
keep your mouth shut! Also, Federal agents aren't going to waste their time prosecuting individual users. (unless they want to flip you) They'll either turn a blind eye or turn you over to the local PD.
Either way I think you're best option is to meet up with someone you meet online (like here.) who has a card and get them to hook you up with some of Denver's finest in exchange for a six pack.
Marijauana is a schedule 1 drug. the federal gov't classifies it in the same group as heroin and other hard drugs. they take weed seriously. even though common sense says they shouldn't, the law says they do.
and of course, the cop are always going to tack on additional bullshit charges like disorderly conduct, public drunkenness, disturbing the peace, etc etc...
I'm going to agree with trucktown here. The Feds don't bother themselves with small time drugs of any variety. State and municipal police do but only cocaine and heroine because the fed pays local governments to prosecute those drugs (but not marijuana.) I can also say from personal knowledge that felony charges related to marijuana will not get you jail time even if they throw in other charges (paraphernalia, conspiracy, resisting, etc) THere are circumstances where it could lead to jail time (third offense, perhaps a weapons charge as well) but its rare. Nobody really cares about marijuana these days. Big Busts (there are alot here in new Mexico) don't even make the news. People
do care alot about money so as trucktown says one only needs to follow the paper trail to see if anyone will care enough to follow through on some charges.