[TomVDB]

If an employers rescinds an offer, the employee could blog about it, resulting reputation damage for the employer.

But who would the reverse be true? It’s not as if there’s a database of employees who have signed a contract but didn’t show up...

[thatoneuser]

The tech giants (or other corps) have spread the fantasy that if you piss one of them off then everyone up there will know and black ball you. Basically unless you don't do anything super illegal the odds of fucking over your employer coming back to haunt you are relatively small. But the fear that it will keeps people in the order the corps want.