Even when their employer claims it happens daily? Or what does "expected" mean?
It means a part of the job. Violence against bus drivers is a problem. Many use shields now. Imagine if they had to work naked and in physical contact with customers.
Few jobs require people to face gunfire or wildfires. That is why police and firefighters are honored by the public. Regardless of whether or not other jobs are actually more dangerous the public perception is that jobs other than those do not require people to risk their safety.
In the absence of a UTI or blood in the urine, it basically is. At any rate, in the absence of a UTI or blood, it's harmless.
Parents can be quite confident their babies don't have a UTI or blood in their urine. That is not the case with strangers. In any case urine is only one of the body fluids I mentioned. The core argument is still supported.