It may be possible that a registration times out and is deleted before they pay or cancel on the payment site. They may then pay the fee, but with no record of registration.
It may be necessary to timeout certain kinds of registrations differently, depending on payment type.
Also, what to do if the postback fails? Maybe all registrations should be hidden instead of deleted. This would require changes in a number of places...
It may be possible that a registration times out and is deleted before they pay or cancel on the payment site. They may then pay the fee, but with no record of registration.
It may be necessary to timeout certain kinds of registrations differently, depending on payment type.
Requires further investigation.