I think the adultery metaphor is a little far-fetched, or perhaps irrelevant, but I understand that privacy is as serious an issue as those things you mentioned.
Perhaps a better approach for startups/businesses is to inform users (perhaps with some kind of UI-friendly alert) that it's OK for them to use your service with a fake email for up to one week at a time (or etc.) - kind of as a trial - after which their account will be deleted.
This shows that you're happy for them to try the service out with no obligation - but if they won't use a 'real' email address, they wont get a 'real' account.
I invert-quote 'real' because, obviously, it's just as possible for them to use a throwaway gmail account.
I think the adultery metaphor is a little far-fetched, or perhaps irrelevant, but I understand that privacy is as serious an issue as those things you mentioned.
Perhaps a better approach for startups/businesses is to inform users (perhaps with some kind of UI-friendly alert) that it's OK for them to use your service with a fake email for up to one week at a time (or etc.) - kind of as a trial - after which their account will be deleted.
This shows that you're happy for them to try the service out with no obligation - but if they won't use a 'real' email address, they wont get a 'real' account.
I invert-quote 'real' because, obviously, it's just as possible for them to use a throwaway gmail account.