Thank you for that explanation, makes sense sort of all though one would expect from Sixt to have this sorted.

Yeah that was Alamo. I will wait and see what Sixt says otherwise I'll go with Alamo, had a god experience with them the only time I rented with them, car was boring but you can't get everything.
Complete coverage with insurances is all I think about when renting a car. I'm not looking for accidents but if something happens I want to be covered. I hade someone drive into my rental car in a parking lot and then drove away. I had all insurances/waivers possible so I called Alamo, they told me to get a police report then go change cars. Besides waiting for a cop this was fixed really fast, imagine being stuck paying for that even if it's not your fault.
I've read Sixt's T&C and from what I can read they cover everything and provide really nice cars, but I've only rented in CA so crossing states is a new case for me that's why i'm looking into this just to be sure.

Okay so with independent franchises each franchise can sort of set there own rules? I.e. the answer I get from Sixt Facebook support or [email protected] might not be correct for the LAS franchise ?

The T&C says that 0.5 cent/mile driven during the entire rental is charged. So I guess that people I've read about must've in some way gone in to another state just for a few miles and expect to be charged just for those miles?