Rules Analysis
Fouls (3.C): It is the responsibility of all players to avoid contact in every way possible.
Avoid contact in every way reasonably possible, while still playing ultimate. Some contact is inevitable, but players have an affirmative obligation to make reasonable efforts to avoid contact.
Any contact that occurs due to the marker setting up in an illegal position (15.B.3) is a foul on the marker.
Non-incidental contact. Again, nearly all contact will be non-incidental with respect to the thrower. This contact must be part of an ultimate-related maneuver (throwing, pivoting, etc.) and must occur with a part of the marker that is illegally positioned. For example, shoving the marker does not result in contact due to the marker setting up an illegal position. Similarly, if a marker is providing disc space, except for illegally wrapping the thrower with their arms, only contact with the illegally positioned arms is due to the marker setting up an illegal position.
Any contact that occurs due to the marker setting up in an illegal position (XIV.B.3) is a foul on the marker. Once the marker has set up in a legal marking position, it is the responsibility of both players to respect this legal position. However, contact resulting from the thrower and the marker both vying for the same unoccupied position is a foul on the marker.
Non-incidental contact. Again, nearly all contact will be non-incidental with respect to the thrower.This contact must be part of an ultimate-related maneuver (throwing, pivoting, etc.) and must occur with a part of the marker that is illegally positioned. For example, shoving the marker does not result in contact due to the marker setting up an illegal position. Similarly, if a marker is providing disc space, except for illegally wrapping the thrower with his arms, only contact with the illegally positioned arms is due to the marker setting up an illegal position.