We call what Dan does a FAS or Forced Auto Stop. Our hybrids have electric power steering so we do not lose power steering during a FAS. If you drive a regular car that has non-electric PS you will lose PS during a FAS and the car will become harder to steer. My Vette becomes VERY hard to steer without PS.

Brakes are a bigger worry IMO. As far as I know all most all cars including hybrids use vacuum to boost braking power. This vacuum is stored up in a cannister and is ususally good for a few applications before it runs out. It is very dangerous to be expecting power brakes only to find that they are no longer working. I advise anyone thinking of doing a FAS to learn as much as they can about their power brakes before the attempt. Pumping the brakes will bleed off vacuum much faster than constant pressure, in fact you can lose PS in a single application if you pump the brakes. I FAS all the time and every once in a while I lose power brakes. This usually happens when I'm forced to slow down unexpectedly a time or two on a downhill only to speed up again with the car still off.

Learn about power brakes here:

http://auto.howstuffworks.com/power-brake.htm

Make sure to check out and understand the vacuum booster animation on this page:

http://auto.howstuffworks.com/power-brake2.htm

Doing a FAS is dangerous so please be careful and make sure you understand what you are doing before attempting a FAS.