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.
Blocking Fouls:
When the disc is in the air a player may not move in a manner solely to prevent an opponent from taking an unoccupied path to the disc and any resulting non-incidental contact is a foul on the blocking player which is treated like a receiving foul (17.I.4.b).
Solely. The intent of the player's movement can be partly motivated to prevent an opponent from taking an unoccupied path to the disc, so long as it is part of a general effort to make a play on the disc. Note, if a trailing player runs into a player in front of them, it is nearly always a foul on the trailing player.
