Rules Analysis
Positioning before the pull:
After signaling readiness, players on the pulling team may move anywhere in their end zone, but their feet may not break the vertical plane of the goal line until the disc is released.
After signaling readiness, players on the receiving team must have one foot on the goal line that they are defending without changing location relative to one another.
If either team fails to maintain proper positioning before the pull, the other team may call "offsides" before the receiving team gains possession of the disc. The offsides call does not stop play, and the Continuation Rule (17.C) does not apply. In games where observers are used, this call is made by the observers. In games without observers, each team may send a designated sideline player to either goal line who has the ability to call "offsides" or offer their perspective on such a call. A contested offsides call results in a stoppage of play and a re-pull.
To contest an offsides call, a player on the contesting team must have perspective at least as good as the person making the call. If the call is made by a designated sideline player, only a similarly-positioned sideline player designated by the contesting team has equal or better perspective.