This year my friend and I are going to GenCon for the third year. It's become an annual trip, and frankly I've been looking forward to it since I confirmed I could swing the finances t his past January. In a bit of a change of pace, a third person is making the trip with us this year and it will be their first GenCon. Mostly we've handled the big stuff for them (housing, pointing out when to register, etc) since my friend and I have it down. This weekend though was event registration, where you can try to sign up for guaranteed seats at events you really want to play.
Mysteriously at a con as big as GenCon those seats go fast, and even if you click the "submit my wishlist" button at the very instant it becomes available you may miss out on them.
However, this isn't something to stress about. GenCon is a huge con and there is a lot going on. Also, people frequently don't show up to events on time, enabling you to grab their seats if you're prepared. Heck, last year I skipped event registration all together and still had a great time with lots of gaming.
So what do you do? Simple: buy generic tickets. Show up to the event early. Be polite.
As a rule, after 10 minutes an unclaimed seat is considered abandoned and they go first come first serve. Some places do waiting lists. Some places don't. Sometimes a waiting list is started but someone doesn't know so you get bad information. Whatever the case, don't be rude about it. Form a line close but not in the way of actual event ticket holders.
Now, this doesn't mean you will definitely get into the event you want. There's a good chance you won't get in if there is super high demand and low supply. However, there is a good chance you will get in - or find an alternative means of experiencing the thing - if you're patient and polite.
You can have a lot of fun at GenCon with just a handful of generic tickets and a willingness to hang around a few minutes. And if you really want to play a game, why not just wait the few minutes to be sure you can't?