Let's change it up a bit, then. A1 is getting ready to make a cut by the sideline - when he does, his heel is on the line. At the same time, B1 holds him, preventing him from making his cut.

What's your call here? I've got B1 with a holding foul.

To me, it's no different - other than we've got a common foul instead of a PC foul.

Remove the ball from the original play - A1 is cutting to the basket, and B1 is stationary on the baseline with the foot on the line. A1 contacts B1 firmly in the torso, sending B1 sprawling. What do you have?

As far as I can tell, out of bounds and leaving the floor equate exactly. OHBBREF has posted the closest defs we have. Note also the verbiage in this case play:

9.3.3 SITUATION B: A1 and A2 set a double screen near the end line. A3 intentionally goes out of bounds outside the end line to have his/her defender detained by the double screen. RULING: The official shall call a violation on A3 as soon as he/she steps out of bounds. The ball is awarded to Team B at a designated spot nearest to where the violation occurred.

In other words, as soon as A3 is OOB, which is very clearly defined, he has left the playing floor. However, merely leaving the playing floor is not a violation.

Also, iirc, the stated intent for this rule, from the NFHS's comments on the new rules the year it was enacted (or perhaps from the prior year, NevadaRef is right about the piecemeal way this was done), had to do specifically with the inequity of allowing the defense to use the OOB area to play defense, and the need to require all players to play the game on the playing floor. Ergo their interpretation that the defenders foot on the line ends LGP.

I have a big problem with calling a violation for leaving the floor in this situation, because though he is no longer on the playing floor, he has not left for an unauthorized reason.

Violation
 

If the violation occurred first, then you call it and ignore the foul. If the foul occurred first then call it and ignore the violation.

No offense intended guys, but I can't believe we are arguing this since there is a spot-on case play that addresses this issue exactly. Look, guys I don't like it anymore than many of you. I even argued many of the points being made here with our VP of training when this interp first came out years ago. However, I'm not given the option to enforce only the rules I like or to interp a rule in direct opposition to the Fed. I don't make the rules. I only enforce them. And the Fed absolutely wants this to be called a block. I respect your opinions, but based on the case play, I have to disagree with you. This is a block.

Don't get me wrong, I don't like that call either! I've stated a couple of times that this is absolutely a BLOCK by rule. All I was saying is that I can see calling the violation for being OOB. What was the "authorized" reason the player left the floor?

As much as I'm enjoying this, I'm typing with a splint on my left ring finger and I can't do this as much as I'd like. I've got to bow out for now.

I don't know how you make this distinction. Either defense is fair game or he's not.

Would you call a violation on a player going around a screen if his foot ever-so-slightly touches the line?
My contention is that he has not left the playing court.

Guys this is not a violation
 

Rule 9-3-3 does not cover this. Intent is required. Every case play regarding this rule has the word intent except for 9.3.3.A, and even that one it is obvious that intent was there. So if you have a violation every time a player goes out of bounds then what do you have on this play? B1 steals the ball from A1 but in so doing loses his balance. Before stepping out of bounds he bats the ball ahead to B2 who has an unobstructed lane to the basket. Before B2 releases the ball on a shot, B1 steps out of bounds.

If your position is that stepping out of bounds is a violation, then you have to kill this play and award the ball to team A. Let's be consistent guys.

This is not a violation. Neither is the defender stepping out of bounds in the OP. We can't invent an interpretation of this rule to give us an out on calling the block. It's a block.

Ok, how do you distinguish between a common foul and an intentional foul? Same idea. If the offense sees the defense is standing OOB and decides to bowl the defense over b/c they are OOB, then I've got the call against the offense.

How do you argue that the player is legally entitled to a "spot on the playing floor" when by rule, the player is not on the playing floor if he is standing OOB?

I'm not arguing that it should be called a violation? I was just asking where you see he was OOB for an authorized reason. You answered. THanks.

And to answer the play in your example, the player left b/c he lost his balance, that is the same as his momentum taking him OOB. He did not intentionally leave the floor. I don't think the player in the OP intentionally left the floor either, in which case I've got a BLOCK. Very easy call IMO that should not have generated 4 pages of debate.

Nobody is inventing a reason to give us an out on calling a block. What those of us arguing against the block are saying is that a defender stepping on a line does not give the offensive player the right the displace that stationary defender.

From your interpretation, a stationary defender who is touching the line has given up his right to be there. Therefore an offensive player may initiate any amount of contact in any area of the body, displacing the defender, and always draw the blocking foul.

Absolutely....in fact, he got there without contacting an opponent at all. This statement in the rule says nothing about what happens after getting to the spot, only about getting to the spot....i.e., you can't push someone out of the way to get to a spot.

Because it is not an unauthorized reason to be playing defense and inadvertently step on/over the line.

Absolutely agree. I was just asking the question. ;)