OK, we can discuss about this, but in my view it is a difference if a manager who opens a tournament, posts entry list updates and draws asks someone else to post the OOP for him or if he posts the OOP telling players to send to someone else.
Players are far more used to the manager of the very tournament posting an OOP than to some other player or even someone who doesn´t play in the same tournament.
In the eyes of the players the manager will still be the one picks should be send to, even if he doesn´t post the OOP, so picks sent to someone else should not count.
I don't think it matters. Players need to read the entire OOP. Managers do a great job of being specific as possible.
"These matches are for xxxxxx round singles and doubles and must be sent to xxxxxxx by xx
Reading comprehension is a part of Tennis Tipping. Sending to the wrong person is no different than sending for only 6 out of 8 matches, sending wrong names, sending after the deadline or thinking it was a 1-day round instead of a 2-day round.
In grand slams we get something like
Everyone send picks to both X and Y
However if you are A,B,C or D send ONLY to X
If you E,F,G or H send ONLY to Y
And it always gets messed up and the managers end up scrambling for hours.