Audi Q5 doesn't have a dipstick...

It would be the common courtesy to call the agency and tell them so they can make the decision. Just like calling them if something is not right on the car. I had to do that once with brakes. The agency (Hertz) quickly got me another car.
Some rental car company will let you drive on bald tires or under 2/32nds of treadlife left. You point it out, they tell you go do a tire rotation and they will pay for it. Might as well get another car at that point. They dont really inspect the vehicles much for the next driver. They just wash the vehicle and thats it.
If it was about saving money, then VAG would have saved even more by also eliminating the dipstick tube like in some BMW engines, but they didn't.
This is fair point besides being mounted longitude having a bigger turbo, and requiring premium the engine is mechanically the same as my Tiguan which has a dipstick.
All of our cars have the "electronic dipsticks" and all are quite accurate one is a 2018 Q5 btw. At first I was hesitant about their use but over time I do like them and I believe they are an improvement. You can check the oil at a moments notice without get oil on your hands. I guess it depends on your willingness to accept change