I'll also say that it varies with the game. clearly a western kentucky or an arkansas state type game, you can show up an hour early and get a decent seat. But for a Texas/OU/Ohio St game, forget about it.
Sneaking booze in isn't that hard I'm sure, I haven't tried it though. They don't normally pat you down but even if they do I doubt they'd find a well-hidden flask. The security guys are really lazy about their job.
The system as a whole is OK, its just that they keep pushing the students further and further back into the corner and the upper parts of the stadium so they can sell more tickets. which really sucks for us when we pay thousands for tuition, but whatever. Mostly if they keep pushing students back, it will make the game atmosphere worse and worse because there are a lot of blue-hairs in the NU crowd, and students really bring the life to any college crowd. Keep the students close to the action.