During our Game Registration last night, it went very well. So far no major issues. We had one double registration for the Con itself early this morning, but seems the game process went okay.
I have an event, it's set to not allow duplicate registrations (ie: Duplication Prevention Override is set to NO)
When you click the registration button and you are already a registered user for the event you get the registration screen which has:
First Name
Last Name
Email
confirm email
security/captcha
The first 3 fields are filled out and you can change them, the confirm email field is blank so you enter the same email field as the field above. Then you enter the security/captcha code and click the "Next Step" button.
At that point next to the first email field you get a RED X in a circle with the following text: You have already registered for this event.
At which point you can click the "Next Step" button again and proceed with another registration... so people don't pay attention to the warning that they are registered... and it should not allow them to click the Next Button again anyway, it should be a dead button at this point, but it's not