I rest my case about dishonorable people not paying even with the nag screen present.
An alternative to the nag screen would be to disable the custom title bar and place a "Unpaid Shareware Version" in the title. This would then be present 100% of the time and would not be a NAG!
It wouldn't force you to wait to get through the door but would still be a reminder to HONEST people that they should pay!
I do not begrudge the author his due and if he becomes a millionaire due to his efforts then heck ya... more power to him!
A billboard is not a nag, it informs people about a product. People who might otherwise never have known you could buy "super snake oil wonder skin treatment" at their local drug store. I believe the locked title bar would get through to more people than the nag screen.
Anyway, Ive said my two bits worth
Regards
Mark