It's fairly uncommon that your options will be under water when they vest, even in a startup that eventually fails. The more common -- and more crappy scenario should this law pass -- is getting taxed on a paper gain, and then later the price drops below the tax basis due to a down-round or something else bad.
Do you get to claim them against your taxes?
If so, given the rate of startup failures, this may be of net benefit to most startup employees.