Split off from http://drupal.org/node/329998#comment-1099076.
In Szeged, we had a big long discussion about t() around the schema descriptions and it was the consensus of everyone at the table (who included Dries) that t()s should be removed from these descriptions. They mess up things because t() isn't available that early, and people discussed that no one is going to take the time to translate technical descriptions of stuff, and it doesn't really make sense since we also don't translate code comments, for example.
Hopefully someone can script this up so it's not too horrible. :)