SUBREDDIT: r/legaladvice
TITLE: Hi. I think there is something legally improper going on with Home Depot / Penske truck rental service.
POST: I rented a truck, drove it 4 miles. 

I initialed a line accepting that I would be charged "$8 per gallon" if the truck wasn't filled up. 

The inspector assessed my usage of the take as 15/16ths because the needle went from the "bottom of the F to the middle of the F". 

The system records 15/16ths as the minimum usage, and that it is 2 gallons. So, while customers are agreeing in advance to pay an amount per gallon, no per-gallon-assessment is being made. If it is apparent that the needle has moved at all, the very minimum you can be charged is 2 gallons. Nowhere in the rental agreement is it stated that there is a minimum charge, nor is there any language speaking to any penalty other than simply $8 per gallon.
TL;DR: 
Penske/Home Depot get you to agree to a per gallon refill charge but have no way of assessing gallons and compare usage on a 16ths scale, thus systematically extracting extra fees than agreed upon.