I agree that the connotations are different, but the way the vesting is written into these contracts, it is essentially a periodic stock grant, which ends as soon as employment does, and with no guarantee that it will continue. In that way it's very much like a salary, despite how it's typically viewed. Perhaps the expectation part of things is strong enough that this could be considered bad faith, but my understanding has always been that if someone doesn't work out as an employee for any reason, they have no claim to the unvested stock.