The CME Group said it will delay the closure of many of its open-outcry futures trading pits, pending a review of its plans by the Commodity Futures Trading Commission, its regulator. http://www.marketwatch.com/story/why-the-cme-group-delayed-the-closing-of-pits-2015-06-24
Amazing to me the CME Group was unaware of the types of orders being executed in the pits. WTF...they had all of the prints and the trade history.
I never knew there were complex orders in the pits, seems unreal that they would have anything other than buy/sell, price, and quantity what with all the insane stuff going on.
Back in the day, they consider a spread a complex order. The electronic trading platforms had not advanced to support spreads and multi-leg orders so the pit traders handled these. Modern brokerage platforms have changed all that.
I don't think they were unaware of the types of orders executed, but, as the article indicated, might have thought the impact of not supporting certain order possibilities (spreads with tails) in Globex would be 'minor', which, looks like, it is not!