Attacking a ball in the Plane of the Net [USAV Rules]

[Seattle32]

A disgruntled setter on the opposite team the other night was upset that I spiked his teammate's overpass into his hands and assumed it was obvious that I'd committed a fault. His teams various explanations included what I thought was irrelevant information: "the ball was partly below the net", "you can't interfere with the set", "the setter has a right to play the ball"-- all common understandings that don't appear in the rule book (USAV).

My teammates and I were all under the impression that the rule is simple: "when the ball is in the plane of the net, either team is free to play the ball" which also don't appear in the rulebook. In short, once the ball touches the plane from the other side, you can spike the hell out of it.

It seems we're all wrong, but the 2009-2011 rules seem completely counter to what I've ever seen officiated:

[USAV 9.0] Each team must play within its own playing area

[USAV 11.1.2] After an attack hit, a player is permitted to pass his/her
hand beyond the net, provided that the contact has been made within his/her own playing space.

[USAV 13.2.1] A front-row player may complete an attack hit at any height,
provided that the contact with the ball has been made
within the player’s own playing space...

As I read this, the attacker's hand must be completely on their side of the plane when contacting the ball. This would make illegal any kind of straight-down crushing of a ball that's only penetrated the plane an inch or two.

So questions:

1. Have you called or seen called an illegal penetration call on a hitter attacking a ball in the plane?

2. Is it feasible to determine whether a contact has penetrated the plane before the follow-through?