[ltorresv]

I don't see where it says it's already a feature. The note itself (not that post) says it might be available in the future but it's not there right now:

Messages and files shared in 1-1 chats are only browsable and searchable in HipChat by the two people involved.

"While admins do not have access to browse or search 1-1 chats through functionality within HipChat, this is an option we may provide in the future for organizations to opt-in to. If made available, it will not be retroactive, and we will be sure to address how affected users can be notified that their chats are subject to viewing by their admins" http://help.hipchat.com/knowledgebase/articles/358098

It does say the organization can email them and ask for that so while technically possible it's not so easy for the admin to snoop.