It's a way for operators to potentially run an exit to mail services where sufficient exits immune to complaints might not otherwise exist. Certainly others have thought it before. Normal plaintext and encrypted messages should make it through a good filter. For which spammers would be the ones to notice. Granted, there are 13 supposedly unfiltered to at least one gmail IP at the moment so the need to run one seems low.
How many (possibly christian?) exits filter porn? And who's noticing it? Why just the other day google search was working but an exit mogrified my favorite underage gay gerbil bdsm pic site. It showed me happy mice in a cage, not gerbils. I was so pissed, I almost reported it :) And I commonly see exits in the UAE bruteblocking sites that offend their religious ideas. Not necessarily the exits doing it, but their upstream ISP. Them blocking a metaforum with an IT jobs subsection is annoying for sure, I just hit newnym. Should the community hunt and flag these exits? Same difference. And of course, if people were using ssl/tls with fingerprint checking, they'd know their smtp session almost went to someone else's spool. Or know their mail went through for sure. Surely everyones client/server is doing their due diligence on that end :) Never assume an exit operates in any given way.
