Right, but for engineers working in startup hubs, is that really a risk? You can pick up a phone and have a parade of offers on your desk in a few days.

At most your risk is missing out on, say, a week's wages between jobs.

There are many of us on an H1-B here potatolicious. Technically I get 10 days to wrap my affairs and leave the country, not to mention losing any greencard application...

I'm also on a H1B, transferring one is trivial, though you're right that green cards make it more complicated.

You may loose your job at start up at the most unfortunate moment. In 2000 you can find 10 jobs in about an hour, in 2001 you could not find one job if you life dependent on it. Big companies do layoffs too of cause - but probability to be cut is lower and they almost always offer generous severance package. Also your personal circumstances may make lay off extremely inconvenient - for example right before child is born or you have medical emergency.

You should definitely get some premium for this risk - how much is open to interpretation.