I believe the people who place the porta potties are the ones that are responsible for cleanliness. The companies are just following the paid schedule.
Is there a preferred vendor for the porta potties or are is there competition? Are there any facilities that have higher end porta potties? Do any of them charge for entry?
This made my day that we have someone out there looking out for us. Cleanliness is essential in these porta potties. Sometimes you just have to go, thank you so much for doing this public service.