Nearly empty gas tank

I rented a car thru E-Z Rent a Car at LAX and the car was about 1/4 full of gas.  No one notified me of this (and it wasn't marked on the contract) and I nearly filled the tank upon return assuming I had to return it full.  So I added $50 in gas (for 100 miles driven) to my $28 car rental.  After complaining to the manager, he told me that it wasn't his problem that I wasn't "smart enough" to read the contract.  I'm guessing this is their usual MO--renters beware, especially at LAX.