Blizz introducing 45m timer on arena matches

Hasn't been posted here as far I can see so I thought I'd put it up for discussion.

http://forums.worldofwarcraft.com/thread.html?topicId=14287209008&sid=1

Blizzard is implementing (sorry I said that wrong, it has already been introduced the scoreboards just need to be updated) a new 45 minute time limit for arena matches. after that the match ends and both teams lose 16 rating.

I can understand why they want a time limit on matches, but why the 16 rating loss for both teams ? Not that any matches last that long right now but with enough resil they might.