Illegal Screen or Not? I'm Thinking Yes...
 

A1 is driving down the lane. A2 wants to prevent help defense from coming over, and "boxes out" the girl who's guarding her so that she can't help on defense.

I don't think 4-40-6 applies here, hence I can't think of any reason this isn't an illegal screen.

What say you?

You haven't provided enough information. Was there contact? Did A2 get to each particular spot on the floor before the defender?

A2 was backing B2 away from the lane.

Yes there was contact, think of it as A2 boxing B2 away from the lane, but A1 hadn't even shot the ball yet.

If contact is made while A2 is moving in this particular play, it's a foul. If she moves and gets to the spot first, it's nothing.

...while also accounting for time and distance that may be required in getting to the spot due to the speed of B2.

You're using 'boxing out' as if you were a coach. Any contact that moves a player off her spot is a foul. If there was team control at the time of the foul, it's a team control foul (when committed by a member of that team); otherwise, it's a common foul.

And was B2 trying to make a defensive play on A1?

You're right that the screening rules apply -- just make sure the criteria for a foul are met.

"Boxing out" as you describe it is displacement. Displacement is a foul whether it's on a rebound or not. B2 has a right to his/her spot on the floor. I've got a foul on A2, team control - push or block take your pick.

However, A2 also has a right to his/her spot on the floor. If it's a legal "box out" with no displacement, I've got nothing. It always amazes me when I call a foul on a player for displacement on a "box out" that the coach will complain and say "he/she was just boxing out."

I agree. If A2 displaces B2 as described, it's a foul.

"Boxing out" falls under screening rules, every time. That's what it is. There are no "box out" rules; well, maybe in hockey, but that's another thread.

True but the OP says A2 was backing B2 away from the lane, so in this case it's pretty clear there was displacement.

Do you mean A2 was displacing B2?

Not necessarily
 

Sometimes when backing out or boxing out a player, the other player gives ground without really any contact. This is usually at the lower skill levels, but it still happens. If the contact causes them to move you have a foul, but if the player gives ground on his/her own do to incidental contact then you have nothing. The player should plant his/her feet and make the contact displace them. Then you have a foul!

Stepping backwards to prevent yourself from falling is not giving ground. I just want to clarify that a player does not need to plant the feet and fall down in order to draw a foul here.