The fact that people routinely fail to see obvious deleterious repercussions of their actions doesn't mean that they fail to see all obvious deleterious repercussions of their actions. If you routinely lay people off before their vesting cliffs, you'd have to pay them more up-front (also you would probably get into legal trouble). Penny-pinchers are very keen on not paying people more up-front (including paying more lawyers). The fact that people routinely miss implications that seem just as obvious that this one does not oblige them not to notice this one.