Why not have the board software do it for me?
Computers are supposed to make lives easier.
Easier for who? If a modification like that is made by webmasters instead of the software authors then the webmaster has to remake the modifications each time the software is upgraded - hardly a fair or reasonable request.
There's nothing wrong with your suggestion but it should only go to the authors of the forum application, as was suggested before. That said, I am not convinced that the amount of spam you receive suddenly dropped by your own implementation of the suggestion you made. By the time you got around to that your email address would be in hundreds of databases and any time you click on opt-out links in the spam simply adds you to more.
Only solution is a new email address and improved management of how it is advertised to people.
For what it's worth, it *would* be a good idea to request it for UBBthreads. Nothing like attacking a problem from both ends, though.
Go straight to the top. It's more efficient and there are fewer breakdowns in communication.