Charging for parking with rental cars.

[◄Chuck►]

I've been thinking about this for a while but really have no idea how to solve it without introducing many new problems.
And about how much money are we talking here? How much money do you wanna charge per minute of parking? 1€, 10€, 100€ ?
And who's gonna set the price? The owner? Or is it a fixed value?
The whole price calculation, and display would become more complex than necessary.
Imagine one owner sets 3€/km + 5€/min, the next one has 2€/km + 6€/min.
Absolute mayhem that would be. And then for what? That you earn 100€ more per day?
Hardly worth the effort. And then, how often does it actually happen?
If you see renting as business, you have to take a few risks. And one is that people just park with it.

But nevertheless, you have one option on your hand. If it's one person that repeatedly causes this issue, you can set the rent price for him to zero. So he wont be able to rent the car anymore.