I made a similar post about entering after the deadline.
This is an important rule for parents to understand so I try very hard to discuss this regularly.
This is one of the toughest things the tournament staff has to deal with you. We work with very nice members and their families, but occasionally their parents enter them after the Thursday 10pm deadline. And then we can't put them in the tournament, because of our deadline rule.
We really can't make an exception to this rule because it is so unfair to the players who got "turned away" in the past. I must try my absolute best to be a fair tournament organizer. And part of that is consistently enforcing the rules.
Sometimes I get a situation like this: A parent enters at 10:01pm. That is a minute late. But then two more enter around 10:30pm. And then two more enter Friday morning. So it's not fair for me to let the person in who entered only 1 minute late.
Before I started using the online form with entry deadline format, things were very hard to organize. It was very difficult to prepare large weekly tournaments when I wasn't exactly sure who is coming. So many last minute changes had to be made that we sometimes started late.
The current format lead to great improvement where, except in the fact that I feel very bad and stressed delivering the bad news. I don't like to disappoint these nice chess families, but I have to be fair.
And on a positive note, I'm usually happy to let the families make up the tournament in the future.