That memo only deals with defensive players blocking below the waist and a clarification of "adjacent" in reference to the sideline. Be sure to remember that your traditional offensive linemen can still block below the waist in any direction anywhere on the field.
This is a really dumb rule change and will be next to impossible to officiate correctly with a 7 man crew on Saturdays, much less with 3,4, or 5 on Thursdays and Fridays. Personally I think they are setting it up to take out blocks below the waist altogether except those right at the line of scrimmage, but until they do we have this.
Blocking Below the Waist
ARTICLE 6. There shall be no blocking below the waist (Rule 2-3-2) (A.R. 9-1-6-I-VII).
Exceptions:
1. Against the runner.
2. Before a change of possession on scrimmage downs that do not include kicks, blocking below the waist is allowed as follows:
(a) Players of the offensive team who at the snap are:
(1) On the line of scrimmage more than seven yards from the middle lineman of the offensive formation; or
(2) In the backfield with any part of the body outside the tackle box; or
(3) In motion;
may block below the waist only along a north-south line (Rule 2-12-9) or toward the sideline adjacent to them at the snap.
(b) Players of the offensive team who at the snap are completely inside the tackle box or on the line of scrimmage inside the seven-yard limit may block below the waist.
(c) Players of the defensive team who at the snap are inside the blocking zone extended to the sideline may block below the waist inside that area until the blocking zone disintegrates (Rule 2-3-6-b) except against a Team A player in position to receive a backward pass.