The docs were wrong for a long time, but looking back at the issue, there was a quiet turnaround in http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-core/....

So, hashes can be considered ordered in 1.9. It's a mistake to corrupt the data structure, in my opinion, but apparently that boat has now sailed. Thanks for the prod to recheck and sorry about the outdated info.