opponent intercepting throw-in pass

[Jurassic Referee]

It's a violation on the defender as per Rule 9-2-11--"The opponent(s) of the thrower shall not have any part of his/her person through the inbounds side of the throw-in boundary-line plane until the ball has been released on a throw-in pass". In this case, there never was a throw-in pass made; the pass along the endline isn't a throw-in pass and it also isn't illegal until a teammate of the thrower actually touches it. The proper call should be a delay warning.

Or maybe you can rule simultaneous violations, with the thrower's team violating R9-2-12 at the same time that their opponent violated --i.e.-"No teammate of the thrower shall be out of bounds after a designated spot throw-in begins".

No matter what you do, remember that we're behind you 14%.