Same as what happens every year. Nothing was done any different.
A number of people had covid before the trip but hadn't had test results back.
They didn't take precautions because nobody had covid so you wouldn't take precautions.
If anybody on the bus was ill, it was covid symptoms are cold and flu like symptoms.
At the moment all the symptoms of everyone who was tested are flu like symptoms with the loss of taste and smell.
Any of them who tested positive have all got the same symptoms. Some of them haven't got any symptoms at all.