definitely needs a limit.
Otherwise you would always have hundreds in your queue. Also if people enter the wrong email address they never get an email and have to wait until the time expires before they can re-register with their desired login/user name.
This is the only downside to extending the time. So perhaps the registration should confirm back their details at the end including their email, and give the new members an opportunity to cancel their registration and start again.
I think many people enter it wrong in the first email box and then copy and paste into the second one, rather than typing it out again.
