I haven't worn a diaper fully exposed at a gas station yet.
However last summer I did pull up to a gas station pump and got out wearing just a pair of shorts over my diaper, my shoes and no shirt.
The diaper waistband was fully visible both in the back and front and the diaper was an ABU Little Pawz diaper so it was clearly visible that it was not a medical diaper.
However nobody said anything to me but a girl gave me a smile.
I have seen an adult around 25 years old or so who was wearing an ABU Little Pawz diaper without any pants and was wearing just the diaper, shirt and shoes.
He got out his car like that and started pumping gasoline.
People who saw him thought it was a cool and he said he liked to make people laugh.
I think he was a diaper lover too though.
I haven't been gutsy enough to do the full exposed diaper yet but maybe I will next summer.