Hertz - Can I return early?

I am returning home, flying into O'Hare, Thursday afternoon. I wanted to rent a car and return it to my local edition Friday morning. Hertz.com says a midsize is $66. This is too high for my taste, so I ran some other combinations. If I rent Thursday afternoon and return Saturday morning, it's $21/day.

My question is, if I returned Friday morning anyway, would they charge me an "early return" fee? It's no big deal, since even if I have to keep the car until Saturday, it's still cheaper than the original scenario. But, I'm wondering if I could save even more $$. Or, am I being unethical here?

No can do, raisin. It will be printed on your rental agreement that an early return may be subject to a different rate or words to that effect. My guess if you turned it in the next day the charge would be $66. Why not just keep it the extra day and still save yourself 25 bucks?

That is exactly what I'll do. Just wanted to see if it was possible to save even more.