It appears that when someone starts the event registration process and successfully gets past the CAPTCHA screen, a cookie is saved in the browser. It someone then moves off this page (without seeing the Cancel button in the lower left part of the page which is pretty easy to not notice) this cookie stays in the browser.
When this person then returns later to the registration page, they get a grayed out entry for the registration type they started with a confusing yellow diamond and confusing mouse roll-over message.I would suggest that this cookie be automatically deleted the moment the registration page is moved off of or the browser is closed.
Current, "Incomplete event registration" only appears when a user enters email (and captcha) and proceeds to next step by clicking on Next. This means, that there is a conscious attempt to register for an event. So, if he leaves the page without clicking on Cancel, it's logical to consider this as incomplete registration.
Also, the system can suggest him to apply for membership or new it - so her can use unavailable registration type. When he leaves there, he can apply for membership and then continue event registration, using the incomplete message.
I'm still reluctant to do change this behaviour. Will be collecting comments.
Walt Bilofsky commented
Yes, that's the way it works. But I suggest that is a problem. Could you please move this thread to the Wishlist?
A member or a visitor can go to the registration form, take a look at it, decide they are not interested and leave the page (but not by clicking Cancel). So they close the window.
Unbeknownst to them, they now have an "Incomplete event registration." And they will be confused when they return and see the nag at the bottom (for a member) or try to register again.
By creating this persistent incomplete registration, WA has probably misinterpreted their intent. So don't assume you know what they want. Ask them.
Recommendation: Regardless of how they leave the page, handle it as if they had clicked Cancel, and pop up the question of whether they want to cancel and discard.
As soon as event registration was started but not finished, there should be a message in the bottom right corner about this with a link to continue. If user tries to start event registration again by going to event page and clicking Register, he should be directed back to his unfinished registration.
If it works somehow else, it might be a bug - can you provide more details either here or write to email@example.com.