Hi,
Not likely.
There are some forums, that test the IP's and if they do not "reverse", the emails usually get dumped as spam, or garbage. Yahoo started this years ago, when their groups were heavily censored and primed, so that spam and such rarely made it to them ... they still did not do a good job, but then, the spam and bad address issue is a very serious problem on the Internet ... which IPv6 was designing to help kill, which ALL major corporations like Microsoft and Apple and Sun opposed ... why? ... it would kill processes in their software that they did not want anyone to know ... in other words, if they do it it's fine, but anyone else is not!
All in all, the likely answer is the expansion of IPv6, which will likely take place by the time that appliances and everything else get "connected", because those folks will also want to know about "their" service and such.
I asked the question to my ol' roomate ... as to why a mail server does not cross reference the IP addresses? .. Easy answer ... your email will never arrive ... because the checking process would take too long to deal with it, and some other issues having to do with routing out there. Basically, only the Inet Control folks can kill the IP and the routing ... by blocking some parts, but spoof'ing is out of hand and things are not going to get any better until the definitions get tougher and get better ... basically, you shold not get an IP without a written statement of this and that ... and if you run a business, your information is open on the Internet!
Right now, too many "sub's" are totally hidden, and there lies another part of the same issue and problem.