Soft ground after October rains: will they still deliver porta potties?

I have a 5K charity run scheduled for this Saturday in a city park. We're expecting about 300 people over four hours, with a food truck and beer garden, so I ordered six standard portable toilets and one ADA-compliant unit. The rental company is due to deliver them tomorrow morning. But we've had heavy October rains this week, and the field where they need to go is now pretty muddy and soft. The delivery spot is about 50 feet from the paved access road. Will they still deliver porta potties onto soft ground like this? What happens if the truck gets stuck? Should I call and warn them, or is this normal?