I understand they do it in part to prevent ticket scalpers.
What was happening was that people would get tickets online, and then sell that on eBay, get money for it, and then show up earlier than the person they sold the ticket to, and then that person's barcode would already be swiped as in. OR, they'd just sell copies of the badges. (The badges have a special cut for authenticity).
To get a press pass, you need to either show creds from the publication, or, if you write for a website, you have to show the website you write for and that you are a writer for it (business card, letter from site stating you're a writer for them, etc.). CC's idea is that the more press, and electronic FAR outnumbers regular press, the better publicity for CC. Of course, it's now sort of backfired, because they get SO much press, and Hollywood's come a-knocking, that the press aren't geeks anymore, but all the obnoxious pretty people from E! or Entertainment Tonight with their hair extensions and phaliic microphones. The incidence of creepy stalker types has grown as well, not to mention violence - someone got stabbed in the eye in Hall H last year, right before Harrison Ford came on.
But yeah, people buy tickets for the following year's Comic Con the year before now. Hotels are a total gamble. You have to wait until the day they announce rooms in March (Travel Planners is the company) and then everyone throws in with their picks, crashes the server, and then you get a room (hopefully) by lottery's pick. Which pretty much guarantees you don't get a hotel within walking distance, because all the studios have blocked out rooms for their peeps, shows, actors, etc.
125,000 attendees descend on San Diego that weekend, and that's not counting the exhibitors, press, professionals (studios, actors, producers, writers, publishers) and redshirts (that's what we call the security people, cuz they wear red golf shirts with ELITE on the back) that are there as well.
But the best advice of all for CC - comfortable walking shoes.