Security breaches are very convenient. First, practically any information revealed can be considered security breach even if you just forward a meeting invite

Security breaches are very convenient. First, practically any information revealed can be considered security breach even if you just forward a meeting invite with a list of coworkers to your private email or you talked to your friend at a party about what you do at work. This is all explicitly, prominently prohibited by contract (not a google employee but any large corporation I worked did that). Second, company can avoid releasing too much information about it exactly because it is security matter. Third, there is usually good track of evidence and it is easy to find. Just look at the mail the person sent outside the company and look for anything they should not be revealing (ie. almost any information). Fourth, there needs to be no precedent for firing employees for security incidents. Companies do that regularly for valid reasons. And yet as or even more frequently, they decide not to react, also for valid reasons.