Maybe I had a different takeaway from everybody else here about this story. It's hard to focus on anything other than the ending interaction.
To me it sounds like the CEO just started panicking and sent you an email so he wouldn't have to do anything relating to fixing or explaining the problem in sales for all his customers or paying you for your work / to fix it. He probably didn't even want to pay for a lawyer, rather than how he played off being nice.
It sounds like he just got away without having to do anything because he threatened you and sold you a cop-out story "But what about the kids?"
That CEO definitely read "How to Make Friends and Influence People" lol
But then again everybody benefited from that approach? If he had really wanted he could probably have gotten them in trouble with the university for cheating.
I can absolutely see how you think that, but I didn't get that impression. There was certainly the thinly-veiled legal threat -- or at least, the implication that it could go that direction if they completely ignored him -- but it sounds like they did take these kids' suggestions on how to harden their system a bit to heart and implement at least some of them. That time isn't free.
To me it sounds like the CEO just started panicking and sent you an email so he wouldn't have to do anything relating to fixing or explaining the problem in sales for all his customers or paying you for your work / to fix it. He probably didn't even want to pay for a lawyer, rather than how he played off being nice.
It sounds like he just got away without having to do anything because he threatened you and sold you a cop-out story "But what about the kids?"