USA pool play
 

Do you see any error or problem with these applications of the pool play compression rule Rule 4.1.D.2 Exception:
In All Junior Olympic Fast Pitch Pool Play Only. When a team
elects to use more than nine batters an out will be recorded if a player leaves
the game for any reason other than injury or ejection. If a player leaves for
an injury and cannot continue in the game, the game will continue with the
injured player(s) batting position(s) being skipped with no out recorded.
Teams cannot play with fewer than eight players.

1) In any such case, any remaining substitute must replace the injured player and the lineup would not be compressed.
2) A player is injured while at bat and cannot continue. That player would leave and the next scheduled batter would come to bat with a fresh count. No out would be called for that removed injured player or for that player’s spot in the lineup.
3) A player is injured while on base or between bases and, after the play, cannot continue. That player would leave. Play would continue as if that injured player had not played at all. No out would be called for that removed injured player or for that player’s spot in the lineup. This is questioned and needs more research
4) If the subject player was a CR, it would be treated the same as any CR injury, i.e. replaced by whomever the CR was running for.
5) If the subject player was the FLEX, on offense for the DP; the DP player returns. That DP player may continue as both DP and FLEX.
6) If the subject player was the DP, the FLEX player must replace the DP player. The FLEX player may not continue as just the FLEX without a DP.
7) A player is injured while playing defense. That player would leave. Play would continue as if that injured player had not played at all. No out would be called for that removed injured player or for that player’s spot in the lineup when it occurs.

Again, the player's stats would still be official including put outs, assists, etc. (If anyone goes to that length in tournament pool play.)

Also, at the bottom of 4.1.D is this:
Effect: Failure to have the required number of eligible players to start or
continue a game will result in a forfeit.

Wow, Harry. There's a lot to unpack here. As a UIC at a 14U tournament last weekend, this very matter arose. I'll get to that shortly, but have added comments above in your OP.

To the tournament last weekend. I was asked to report to a specific field due to an unspecified issue. Between innings at the backstop, the plate umpire informed me that there had been an ejection. The coach wanted to know what the penalty for the player might be.

Once the game concluded with the ejected player's team having won the game, the PU turned over her lineup card. The team had batted all 10 players present. The ejected player's name was crossed out on the lineup card. No out was taken when the missing player's turn at bat came up.

This tournament's rules indicated that any player, coach, or spectator that was ejected would be suspended for the rest of the tournament. I informed the coach of this rule and he was not happy about it. (Ultimately, the Tournament Committee decided the player would receive a 1 game suspension.)

As we researched the situation of the ejected player, I maintained that the game should have resulted in a forfeit. Some were of the opinion that it didn't matter since the team had not dropped below 8 players.

I did some research from ASA/USA SB Plays and Clarifications.

From August 2019:
Play: Team A has 10 players and decides to play with a DP / Flex. In the 4th inning F2, not the DP or Flex, is ejected. Team A now wants to take an out each time F2 comes to bat and continue to play shorthanded.

Ruling: Since F2 was ejected and is not the DP or Flex Team A cannot play shorthanded and the game becomes a forfeit. Rule 4, Section 1D [2A] Effect, Rule 4, Section 8D

When this rule was first introduced, it was kind of messed up. You could bat everyone, but if an EP entered the game on defense, this was considered a substitution. This messed up many coaches and umpires. Ultimately it was changed to be more like the slow pitch EP who could also play anywhere on defense.

That's enough for now.

I have to study your comments further, but I believe the "compression" part of the rule is intended to avoid automatic outs for non-ejection departures. My OP was about applying the compression or not.

Yes, if full roster, which means no substitutes, an ejection would be a forfeit.

My "had not played at all" was about the effect on lineup and applying the rule by an umpire. Stats are an aside.

Reference:
"Also, at the bottom of 4.1.D is this:
Effect: Failure to have the required number of eligible players to start or
continue a game will result in a forfeit."

The key in that is "required number".
The required number is in the list under A, then the exception.

Referring to:
" Between innings at the backstop, the plate umpire informed me that there had been an ejection. ... skip ...

Once the game concluded with the ejected player's team having won the game, the PU turned over her lineup card. The team had batted all 10 players present. The ejected player's name was crossed out on the lineup card. No out was taken when the missing player's turn at bat came up.
... skip ...

As we researched the situation of the ejected player, I maintained that the game should have resulted in a forfeit. Some were of the opinion that it didn't matter since the team had not dropped below 8 players."
---------------------------------------

Of course it was a forfeit if they had no sub for the ejected player.
Why did the inning continue until "between innings"?
There is never an out taken for an ejection, either a sub or a forfeit.

The head count only matters for non-ejection removals.

The PU was not familiar with the pool play penalty for ejection. And further thought after discussions with some other folks that an out SHOULD have been taken in that spot which was also incorrect.

So we live and we learn.

This week's tournament removed the suspension for ejection and add a statement that an ejected player in pool play on a team batting everyone would be an out.

I'm OK with that if that's how the tournament director/sponsor wants to play it. At least it's addressed. The one last week with the team with the ejection winning the game didn't feel right.