I'm sure people get approached about match fixing in all kinds of sports. And while the top tier of tennis players certainly make more than enough money not to have to worry about stuff like this, there are others who are just scraping by playing on the tour and could probably use the extra cash.
That said, there's a strong argument that the betting data alone cited by Buzzfeed isn't enough to prove match fixing:
http://fivethirtyeight.com/features/why-betting-data-alone-cant-identify-match-fixers-in-tennis/
Follow the links and they'll show with a reasonable degree of certainty that Lleyton Hewitt was one of the players identified as a potential match fixer, and that examining the individual matches in question shows there were much more likely explanations than match fixing in every case.
That said, there's a strong argument that the betting data alone cited by Buzzfeed isn't enough to prove match fixing:
http://fivethirtyeight.com/features/why-betting-data-alone-cant-identify-match-fixers-in-tennis/
Follow the links and they'll show with a reasonable degree of certainty that Lleyton Hewitt was one of the players identified as a potential match fixer, and that examining the individual matches in question shows there were much more likely explanations than match fixing in every case.