I don't think there's any way Ben could have known that she claimed on her personal tax return an exercise date for her options that was not the actual exercise date. I doubt the Feds knew that when they issued the Wells notice. Her ex-company probably didn't know. At the time of the Wells notice, she was probably the only person who knew she had lied on her tax return.
And, though it sounds silly after the whole stock option backdating brouhaha, many people did not seem to think that these practices were illegal at the time. Even Steve Jobs was accused of it (though never charged.) United Health Group, KB Home, Brocade, and Monster Worldwide all had executives who were found to have broken the law on backdating. It's possible these executives did not think the practice was illegal (maybe because their accountants had told them it wasn't) and likely they thought that it was a law not enforced (because it had not been enforced until the WSJ brought the practice to light in 2006.)
"Even" the guy who stole from his business partner and supposed friend? The fact that Jobs was doing something isn't much argument that it was legal or right.
And, though it sounds silly after the whole stock option backdating brouhaha, many people did not seem to think that these practices were illegal at the time. Even Steve Jobs was accused of it (though never charged.) United Health Group, KB Home, Brocade, and Monster Worldwide all had executives who were found to have broken the law on backdating. It's possible these executives did not think the practice was illegal (maybe because their accountants had told them it wasn't) and likely they thought that it was a law not enforced (because it had not been enforced until the WSJ brought the practice to light in 2006.)