[Johnny555]

So they start looking around for alternatives, which I hear are plentiful at the moment

On the other hand, if you think the layoffs are due to an impending economic downturn, you could end up moving to a new job and being the new guy, so if they need to make cuts, you're first to go.

I was working for a small (~500 people) but well established startup around the time of the original dot-com bust. I have some friends that tried the same thing -- saw the writing on the wall and tried hopping to a bigger more established company for job protection, but they were the first to lose jobs when layoffs hit the industry. We had relatively layoffs in some areas of the company, but not in the core engineering team.