This is exactly why these boards offer the option to provide one e-mail address for our administrative use only (this one is not never ever visible to other users) and an e-mail address which will be displayed on posts and in your personal info. It is left to your own discretion to smartly provide the public, none, or a fake public e-mail address.
You could fake it and strill be reasonable reachable with pretty simple measures like
tjerk.nospam@mirc.com or
tjerk@nospam.mirc.com or even
tjerk@reverse.crim.com like addresses.
Succes!