I’ve taken cars back with so little fuel I genuinely thought I was going to run out of fuel on the 20 mile journey to the dealership! I did take a can of petrol in the boot and drove like my granny the whole way there.
I did this because I had a feeling the new car I was due to pick up had zero fuel in too, I was correct as the dealer advised me not to drive past the petrol station a couple of hundred yards down the road…
I did get a Mercedes A200 a few years ago and it was totally full of diesel, the dealer made a point of telling me (and the rest of the showroom) the car was full of fuel.
I wouldn’t allow a dealer to put “£25 worth of fuel in the car” I’d rather take it and fill up knowing there was £25 worth in the car – I’m not saying dealers are untrustworthy but just for my own piece of mind.
So different cars, different dealers, different manufacturers in my experience