script/server and irbrc

What's the reason that script/server loads your .irbrc for every page
request? It seems dangerous to me for a couple of reasons, one is that
it might make your development environment drastically different than
your production environment (especially if you use GuessMethod or any
other method_missing/const_missing hacks in irb). And it can fill your
server terminal window with tons of unrelated-to-your-app error
messages about undefined methods on nil if you do something like
configure an irb prompt (with IRB.conf[:PROMPT]).

I've resorted to wrapping my entire irbrc in unless $0 == 'script/
server' ... end, but that seems like an inelegant solution.

So, why does it do it?