David Leimbach wrote:

Just refuse to use UHC until it conforms.  One can refuse to use GHC libraries that use extensions as well for similar reasons.  I always think twice when I see something that isn't Haskell 98 in my stack.

Do you not use Hugs for the same reason?

http://cvs.haskell.org/Hugs/pages/users_guide/haskell98.html#BUGS-HASKELL98

Martijn.