I had an office neighbor whose entire practice was setting up small businesses as S Corps, then having the owners pay themselves no salary.  And he said he always got away with it.  But that was 15 years ago.  These days, though, there may be enough of those left that IRS will go after those paying no salary, before they go after those paying some salary.  

IRS is never too small to be bothered.  Look at all the EIC audits they do.  On the other hand, there was someone posting recently about the fear of a "hobby loss" audit.  I had a client with losses in the $50,000 range for many consecutive years, and we always had to remind ourselves that all the court cases involved horse breeders with $500,000 losses.  (And some of them won, because the value of their real estate kept increasing and they had to farm to keep the property taxes low.)

Not just S corporations, with a lot of small businesses it's the owner who makes less than the employees.  There is often no comparison because no one would hire them; that's why they created their own job.  And why start with a reasonable salary?  Why not start with a reasonable return on their capital investment?  If anything is left over, that's what they get paid.