warmer fuel?

[Olympiadis]

Right. If you don't have a return-style fuel pressure regulator then you're in luck because extra tank vapor isn't an issue.

I was talking about return-style systems, which is what I'm almost always working with. It's not always a bad thing, and if you route the extra vapor back to the intake the adaptive fueling will cut back a small amount on the injector pulse-width. Ideally all of the tank vapor gets routed back to the intake and burns. The main problem with the warm fuel (if it's too warm) in the tank is pressure build-up after engine shut-down.
A similar circumstance is created whenever a heat-shield between the exhaust and the fuel tank falls off. I have seen it expand the fuel (and vapor) to the point that fuel would leak out of the fill-tube and high-pressure vent.
Warm fuel does expand and will therefor throw off your fill measurements and mpg calculation if you're filling at inconsistent fuel temps.