Boy you need to wake up andiwm - there are all kinds of safeguards, the biggest being anti-competition clauses in contracts. Any employee of this caliber would be required to sign one.
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that makes me chuckle. seems you're the one who isn't fully awake.
BTW.: your logic is flawed:
As for safeguards in my contract like NDA's I can decide if I sign them or not. That is a free market with a free contract. And even the non competition clause are limited in their validity by law. And at least the ones I signed so far clearly state that only direct competition is prohibited, not working for a company in a related business in general. Read yours and you'll see.
Corporations deciding with back-room deals without my knowledge who I can work for or not is not free market.
And yes theoretically I can leave my job at any time in case I find out that my employer agreed with some other company that they don't poach me. But now wake up: the fact that some Exec VP tells some low level HR person not to "poach" employees from company X leads in real life to the fact that the HR person does not hire any person from that company X because she/he got the message and doesn't want to piss off the VP. Working in a company with many partners then leads to the fact that you can't get any job elsewhere. I have seen that and I have been part of those deals. Believe me it's disgusting.