I serve on the PASS Board of Directors, but this post reflects my personal views and not an official PASS position.
One of the things that has always interested/amazed me is how many people wait until the last minute to register for PASS, and that wait typically results in spending an additional $500-$1000 more than you needed to. Early bird registration is $1195, and that's an entirely reasonable cost for any conference, and what you save by getting the early bird rate would cover most of your travel expenses.
So why do people wait?
One big reason I've heard is that they are unsure of their schedule and what will be going on at work. I know work can present challenges, but if you asked to schedule vacation right now for November would it be approved? If so, how's that different from scheduling training? Both require checking for existing conflicts and figuring out who will cover for you while you're gone. One thing to note is that PASS allows transfer of the registration without penalty, so you can register the most likely person to attend and if things change, send someone else from your team, or maybe your manager!
Another reason is money. Businesses like to procrastinate on spend, but that's not always good stewardship of money. Why spend $500+ more than was needed to delay the decision a couple months? If the money just isn't there yet that makes sense, but more often it's just a tradition of let's wait and see. Not only does that increase your cost to attend, it decreases your ability to save money on hotel and airfare by starting to look well in advance.
From an attendee perspective the first and most important battle to win is that you need training and that you think the Summit best fits your needs. Part of a strategy of winning that discussion is to show your employer that traveling to training is possible and that you are looking at ways to get the training you need at the lowest cost to the company. If the company just insists on waiting there's not much you can do, but seriously, doesn't it make sense to register early in most cases? Not all, but most?