Apple got a mixed response when they pushed back on the FBI, but certainly not a clearly negative one. Lavabit's rather alarming case earned them substantial respect in the tech circles that learned about the matter.
Certainly whistleblowers have faced immense consequences, but they've been government or military employees engaged in major disclosures. To jail a 'captain of industry' for reporting that the government handed her a sheet of paper would be spectacularly bad optics, attacking a respected private citizen over an intuitively absurd legal mandate.
I suppose the details of the account in question would become important. If the public can be persuaded that you blew up an important investigation, you probably lose all support; we've certainly seen the government disclose a surprising amount of formerly-secret material to turn public opinion against whistleblowers. Even there, though, you could test the gag order by disclosing the fact of an NSL without the content.
If they can't show overwhelming importance, though? If it's just a cartel bust or a leaker or something similarly non-terrorist-y? I'm trying to picture the government bringing the hammer down on Cook or Mayer for going up on stage at a conference and unashamedly violating an NSL. It doesn't seem like a good fight to pick.
