I don't think they are irrational thoughts, I think like that all the time. Most prep set ups will be similar to preschool which means parents will still have to sign in their kids and the toilets are attached to the pre-school prep building. No other students or staff should be able to access these and students are generally able to be supervised (not watched)

I guess we just have to let them go no matter how much we worry and just hope nothing goes wrong