Isnt the ball either on the inbounds or out-of-bounds side of the plane?

Why does the ball have to be completely out of bounds? If the defender reaches through the plane and touches the part of the ball on that side, it is still a technical, is it not?

It isn't really where the ball is that matters. It is where the defenders hands are.

If the defenders hands remain on the inbounds side of the plane, you have a legal play.

If the defenders hands cross through the plane, you have an illegal play. The penalty depends on what they touch while reaching through the plane. If the touch nothing, delay of game. If they touch the ball, technical foul. If they touch the thrower, intentional personal foul.

(Note that not reaching through the plane but touching the thrower has reached through...presumably with the ball....has also recently been declared an intentional personal foul. It doesn't make any sense, but that hasn't stopped the recent rules committees from making changes).

So no warning on on the first time they do it? Warnings only on inbounds plane violations and not hitting the ball?

What if the thrower has broken the plane with the ball and part of his/her arm.

In attempt to play the ball, the defender makes contact with throwers arm - which has broken the plane?

Is this an intentional foul or common foul?

No. A T or an IP foul is ALSO the first warning. If they then break the plane again (without hitting the ball / arm), it's another T.

Intentional

Unfortunately, that is the current ruling.

It doesn't really make sense that you are allowed to play the ball but if you miss and get a little arm, you get an intentional foul, but that is what the rules committee has decided. I think they have a minimum quota of nonsensical rulings that they must make each year.

Well I guess we could treat that as incidental unless the contact rises to the level of an intentional foul. Not exactly what they wanted but I'm just saying...

Furthermore ...
 

The defender may not break the imaginary plane during a throwin until the ball has been released on a throw-in pass. If the defender breaks the imaginary plane during a throwin before the ball has been released on a throw-in pass, the defender’s team will receive a team delay warning, or if the team has already been warned for one of the four delay situations, this action would result in a team technical foul. If the defender contacts the ball after breaking the imaginary plane, it is a player technical foul and a team delay warning will be recorded. If the defender breaks the imaginary plane, and fouls the inbounding player, it is an intentional personal foul, and a team delay warning will be recorded. It is an intentional personal foul if the defender fouls the inbounding player, even without breaking the imaginary plane, however, in this specific case, there is no delay of game warning because the defender did not break the boundary plane.

Don't think so. If there's contact, it's an intentional foul. Now, if the contact is missed, ...

Sure it does. Before the change, the penalty for hitting the ball was more severe than the penalty for hitting the player.

Good point, I guess in this case there is no such thing as incidental contact. I still don't like it.

Wonder about contact with the hand....

What penalty for hitting the ball? It was LEGAL to hit the ball. Remember, the contact we're talking about is on the inbounds side of the line.

Intentional Foul.