CEE's were always required, but back in 2005 or 2008 IIRC they discovered because of how it was worded (said if available, or when available or something like that) they were finding they were seldom used because by the time the EC showed up to work the footings were already done and access to connect to the CEE wasn't all that "available". So they changed the wording to remove that if or when available to what it is now and basically requires you to connect to it if present, but did add exceptions for existing construction so that you don't have to cut into a footing just to connect to the CEE that may or may not be present.