agreed, that's really annoying; I posted about this already a while ago and Lukor replied saying that he thought after all it would be more secure to have the pop up each time, referring to mobile devices, and there would be later an option to deactivate that; he asked me if that was a good compromise...don't know why I said OK but realized almost immediately this was no solution, because deactivating it could lead to having no info about new detected networks however it happens, even at home...not mentioning that if you forget to turn it back on (the notification) you'll get surprises in public places, if you don't want to connect for instance.
Best behavior is how it works with most other firewalls, one notification each time a new network is detected, and never again, unless you've switched to another one in the meantime, and come back to one you already used. So as far as I'm concerned, the recurring pop up each time you reboot is a bug, and there shouldn't be an option for that, it just shouldn't happen.