I'm thinking that they are going to be opening up registration in the next 2-3 days, as their wording from the emails implies it is within days now.

The email from today that Paulbot quoted said "take one last look" at the brochure, while the one they sent out yesterday was letting us know that registration wasn't starting today (Tuesday - Monday night in America).

From Yesterday...

Just so you can quit checking today. Registration is not today. However, you do need to go to TransformersClub.com/shop and make sure your log in works (click on My Account and log in). If it works in the store, it will work in the registration system. If it does not work you may need to renew your membership. If you have any issues, please let us know.

In addition, if you have an issue with your credit card company, please do not call us. Only your card company can fix any approval issues.
What was really interesting though, was the wording on Saturday's email (Friday in America), thanking us for the last 12 years of supporting them... which sounds very final.
It also noted that registration would start next week (which is this week).

It is almost time to register for BotCon 2016! We will begin registration for BotCon, North America’s largest Transformers fan convention, next week. We will send out an email when it goes live and will also send updates via our Twitter and Facebook pages. Follow us to stay in the loop on the latest BotCon announcements!

Speaking of Facebook, for your first look at PREDACUS, the combined mode of the 5 figures from this years boxed set, visit our Facebook page here.

Thank you for your support over the last 12 years as we look forward to seeing you Louisville, KY, April 7th-10, for the biggest and best BotCon yet!