Mindboggling Ref Miss?

I was just watching a recording of the Nuggets-Hornets Playoffs game 2 from earlier this week, and I saw quite possibly the most blatant foul that was never caught in my time as a basketball fan. The refs didn't see it, the TNT pundits didn't see it, the coaches and players apparently didn't see it, and since I've heard not a peep about punishment from the nba, I'm assuming the brass didn't see it either. The situation:

It is early in the 4th quarter, and the Nuggets are up a dozen points. J.R. Smith has the ball on the perimeter. After some twisting and turning, he creates space and fires a loooong three-pointer that goes in and pulls the crowd to their feet.

As Smith shoots, Nuggets forward Chris Andersen moves towards the basket, getting ready to grab the rebound in case Smith misses. As he runs into the paint, Hornets defender James Posey appears to get in position to box Andersen out in order to secure the potential rebound at 10:10 on the game clock. Andersen runs into Posey's rump and falls like he just ran into a tree. Lying on the ground he waves at the refs indicating that he got fouled.

After viewing the recording over and over, I saw nothing wrong with Posey's boxout. The player who was guarding Andersen and followed him into the paint, Hilton Armstrong, also did not appear to commit a foul. I recall Posey being known for the occasional cheap shot, but no amount of replays could convince me he had done something wrong. Chris Andersen however, appears to have strongly disagreed and "voiced" his disagreement in the next play 7 seconds later:

After J.R. Smith's downtown three-pointer, the Hornets'  Chris Paul brings the ball back up the floor. Before the Nuggets' defense can settle, Paul drives past defender Anthony Carter and nails a short-range jumper. Apparently Paul's drive snagged the eyes of all 3 referees like tractor beams, because NONE of them saw what was going on on the perimeter.

At 10:03 on the game clock, just as Chris Paul is getting ready to school Anthony Carter, James Posey (who played the inbounds ball after J.R. Smith's basket, and therefore is lagging behind the play) has just crossed the half-court line on his way to join the offense. But before he can get even close to the action Chris Andersen charges in from behind and lowers an elbow into Posey's back, sending him sprawling so hard that he slides from nearly half-court to the free-throw line. This is clearly a technical foul. Andersen already had 1 technical a few minutes earlier (for accidentally landing an arm on Chris Paul) and should have been immediately ejected. To be fair his first technical was undeserved, but this one clearly was not. By all rights he should have been out of the game.

But nobody saw it. I feel like a character in one of those movies where everyone except the protagonist is insane. How did everyone in the building miss this?

And while we're at it, what is your most memorable NBA blatant-foul-that-never-got-caught moment?