You forget about the middle corp caste, whose lives depend on those 'disposable' projects. They will do whatever it gets, to both keep their job, and get it done. They're a lot more ambitious than the high-ups, because there's more for them to gain...
An ambitious Security Chief will make his facility as impervious to intrusion, as it gets, whatever means neccesary...
A Spider will use his contats and illegally beef up his facility's home network.
A Corporate Mage will use his own resources to keep intruders at bay, not only what the corp approves.
All of them get scolded, if they succeed. Then they get 'demoted' to another post... But surprisingly one with more perspectives and better paycheck. The corp in question might officialy not approve their methods, but it will reward their success.