ActionMailer: bug or not a bug?

I ran across this when trying to use ActionMailer separately from rails:

[09:38 AM] [bmoyles@bmoyles-mac]
~/tmp $ cat foo.rb
#!/usr/bin/env ruby

require ‘logger’

logger = Logger.new(STDOUT)
logger.info ‘Testing-1-2-3’

[09:38 AM] [bmoyles@bmoyles-mac]
~/tmp $ ./foo.rb
I, [2006-06-13T09:38:26.171334 #11749] INFO – : Testing-1-2-3

[09:38 AM] [bmoyles@bmoyles-mac]
~/tmp $ cat bar.rb
#!/usr/bin/env ruby

require ‘logger’
require ‘rubygems’
require ‘action_mailer’

logger = Logger.new(STDOUT)
logger.info ‘Testing-1-2-3’

[09:38 AM] [bmoyles@bmoyles-mac]
~/tmp $ ./bar.rb
Testing-1-2-3

Notice how including action_mailer causes all date/priority/etc info to
be stripped? Is this desired behavior? I dug through action_mailer a
bit and couldn’t figure out where this was being borked… Any
thoughts?