I have read both sides of the story and I see valid points in each.
If the situation was not explained correctly, it is not her fault for enforcing the rules. Had the extra additions not impacted the timing of the event, I personally would have let the players participate, but then again it was not my call. I do understand the frustration involved with people being late (there are very few valid excuses) - I usually aim for 15-30 minutes BEFORE registration even opens to ensure I find the correct location and can get my decklist together early before people decide to start scouting.
The right call was made (obviously) to go back for the insulin. This should have been communicated to the TO - and if it was, an exception should have been made.
My main reason for coming into the conversation is to prove that a first round loss is BAD. While it is easy to 'Ride the Wave' as I call it, you are always better off winning than losing.
If you are 0-1, you need to make 5-1 (assuming 6 rounds) to make top cut. This means that you need to face:
0-1
1-1
2-1
3-1
4-1
If you are 1-0, you need to make 5-1 (or possibly even 4-2) to make top cut. You need to face (worst case scenario):
1-0
1-1
2-1
3-1
4-1
When comparing the two, we see that the only difference is that the late player has to face an 0-1 whereas the early winner has to face a 1-0. The late player HAS to win the 2nd round to make cut, but the early winner can lose the 2nd match to be at the same place as the first player.
If pairings are made by S.O.S., these two players would be essentially facing the same caliber of players by the third round (players that didn't lose to an undefeated player). So while it is easy to recover from a first round loss, it is much easier to win your first game and continue. I realize that there are other factors to consider in pairings and percentages, but the first few rounds anything can happen (if two good players face off R1, one will be 0-1), and the S.O.S. evens out in the middle rounds.