Re:Why give notice, then?Resign effective immediat (Score 2, Interesting)

Of course, I live in the UK, which has substantially better labour laws than the US...

This is the real crux of the issue. In the US, an employer can generally fire you "at will or at whim." This applies even for highly-skilled, white-collar professionals. It's also not uncommon for an employment contract to demand lengthy notice in the event of resignations (two, three, or even six months), while clearly establishing that your employer can terminate your job with no more notice than the time it takes to say "You're fired."

In addition, "golden handcuffs" are getting more common: Leaving your employer (even if through a no-fault layoff) often means you must immediately repay stock options, retirement fund matches, educational benefits, and bonuses from the last year or two.

And on top of all that, non-competition clauses are growing downright exploitative. A friend of mine is working under a contract stipulation that basically says "if you quit your job, you'll never work in IT in this state again."