There will always be companies or individuals that find a way around regulations. I am sure there are others who never got caught.

If you look at the statements of all the gas producing companies Exxon's does not seem to stand out.

While you do not trust them I am guessing that you are only assuming they are fraudulently under reporting how much they make.

Who knows. Every other company is selling gas at around the same price or lower so it really does not matter.