I assume the intention of adding “focused on” to the definition of guarding should make it clearer that a defending player cannot claim guarding a player while poaching (Pick) or being part of a defence cup e.g. facing the disc instead of the player while crashing (Double Team).
As this is an addition to the rules all previous instances of Pick or Double Team are unchanged. I would hope that it helps the discussion about Pick / Double Team but time will tell.
It is somewhat similar to the addition about jumping / diving related to the question of who created the contact. I like the addition but we will see if it works as intended.