There is a general problem with publicly available email contact information. I would prefer to solve the general problem.
I'd say that if you are out to generalize, there is a general problem of SPAM. Why not solve that instead? 1/2 :-) Seriously, I think that effectively removing contact information from the database is much too similar to sawing off your foot at the knee because you have an itch in one of your toes. I mean, how long will it take before all and everyone needing (out of policy) or wanting to have their contact information publically available to install an auto-filter which will toss messages with "unknown" digital signatures ("of *any* kind"?)??? I think it'll be easier and quicker to deal with the SPAM problem itself before we get there. Besides, the contact information also currently serves as a means for anyone to get in touch with the domain holder or the technical administrator of the domain, in conjunction with e.g. security- related events (yes, I know, it's maybe not fully reliable, but what else is there?), and those messages, even if they were digitally signed, would probably come from an "unknown" key-holder. In all, I have serious misgivings about this general idea of removing contact information from the database. - Håvard