"she is a lousy bus aide" doesn't excuse the children's behavior.
No, it doesn't. But by being a lousy bus aide, she set herself up for an incident like that.
I've had to expel two kids from the bus for "insubordination", and threaten to do so to 2 others. You don't get to tell me 'whatever', or blow off my orders or get lippy with me. That earns a 'major' writeup which often gets a suspension, separation from their friends by assigned seating, and if other kids join in, the whole bus gets assigned seating and loses radio and food priviledges.
Then again... day one I announce to the kids "I am the mean bus driver. I will let you earn priviledges if you behave well. Just obeying the rules is not enough to earn these priviledges. I also believe in collective punishment if I cannot find the culprit responsible for breaking rules so don't hide them. You will be punished too then. BUT if you behave maturely you will find my bus to be a fun place. You can sit with your friends, eat and drink or even get the radio if there is one."
They usually figure out I meant it by week 2-4 of testing me on it. They also learn I will enforce the rules to the last trip.
All the drivers I saw who were successful with problem buses with out of control kids were the same way. I've been tipped and rewarded by parents for doing such a good job, and schools have specifically requested me to handle charters because I am strict with the kids. I took that as a great honor, because I've also had children who were problem children beg me to come back and be their driver next year. That is the best praise of all.
That aide was on that bus because one of three reasons. 1. State law. 2. Special Needs. 3. Bad kids. If it's anything but #1, she failed in her job, last day or no. Is it sad, but I'm sure she's gotten a lot of whispering about her in the driver's room about not doing her damn job and why she got rewarded for it when they all face that and worse every day.