Just read the article.

It's in his vehicle plus everybody who went in for free gas after them. He didn't lock up the pump afterwards.

Sounds like a social media thing. He does it somewhere and tells folks about it because they start lining up there. Modern day Robin Hood, kinda.

That is only 16000 miles at 20mpg. The average American drives 12000 miles per year. It isn't clear over what time period this was done over, but it is only a bit over average if this is in a year.

The article seems to imply per incidence, but even then you only need 50 friends. Or you can cover you tracks just by making the change, then letting an hour go by before going to fill you tank - making it seem like you were one of the lucky ones to get the cheap fuel.