Have you ever heard of a burner phone? Criminals use them all the time in shows to communicate back and forth with fellow business partners or anyone they're doing business with. You don't have to give out any real information to get an account for the phone and they're cheap so you're not out any money when you ditch them.

I think thats why they all had flip phones, much better visually seeing them snapped in half lol jk

So that no one can check what calls they made if they find the disposed phone (redial and whatnot.)