A breach of the rules due to non-minor contact between two or more opposing players is a foul.
Non-minor contact that occurs accidentally is still a foul – it does not need to be intentional. In fact there should be no intentional contact in Ultimate.
Foul: Non-Incidental contact between opposing players (see 3.F for a definition of incidental contact). In general, the player initiating the contact has committed the foul.