So I'd agree with Campo entirely.
And if some "dammed parents" (sorry but the irony here made me laugh, as I have many friends and family who are teachers) were in your classroom, or in a classroom environment (like an excursion), and got in your way or made it difficult to teach, I think you would be happy to have a clause in your contract, which would enable you to go up to them and quietly and politely remind them that you have a role to play, a task to complete, and that their actions were hindering your work. Lets be honest here, you would appreciate that wouldnt you ?