In my (admittedly limited) experience with peering I've never seen a contract. Lots of ad-hoc verbal agreements, and occasionally emails outlining a mutual understanding, but because it so often is obviously beneficial to both parties it is almost always handled in a casual way and decisions are deferred to network engineers for engineering considerations. I've never seen legal get involved. If Verizon brought it to a point where it is a contract dispute then it would be just as much of an indictment- it doesn't change the substance of the post at all.