Problem with exit nodes DNS

[Michael_google gmail_Gersten]

With the recent discussion about nasty exit nodes, I decided to try to
use a fixed set of exit nodes.

I found out that if my exit node was "whistlersmother" or
"BostonUCompSci", then attempts to connect to "adultswim.com" or
"www.adultswim.com" would fail, with an unresolvable name error.

Those sites do exist, and could be found with other exit nodes.

Now, my guess is that these sites are running some sort of "anti
X-rated site" filter on their DNS, and it's making some bad guesses.
But more importantly, how can we check for bad DNS resolves better
than we currently do?