Hypermiling | Saving Gas or Endangering Lives?

Hypermiling has become very popular lately due to high gas prices. Many drivers are practicing hypermiling to extend their mpg.
I understand the excitement hypermiling can cause when you see substantial increases in your fuel efficiency, but at what cost?
As with other things in life, there are also hypermiling fanatics. These are the ones who scare the pants off me.

Hypermiling Saving Gas or Endangering Lives?

I am all for saving gas by hypermiling, but I refuse to endanger my life or the lives of others, and some aspects of hypermiling does just that.
Drivers are posting their hypermiling techniques online and some of them sound very dangerous.
Slowing down to save gas is a great idea, but I’ve seen drivers claim they are slowing way down, even on highways.
That driver is putting other drivers in danger if they are doing the posted speed of 70 MPH, and this driver is doing 40 MPH. If there’s traffic congestion, then there’s nowhere to go.
Other drivers are posting their hypermiling technique of turning the engine off and coasting. That is dangerous on so many levels!
I am all for saving gas, and if hypermiling is the answer then fine, but the fanatics out there trying to outdo each other with their hypermiling techniques are just endangering lives.
Post your safe hypermiling techniques in the comments so we all can save gas safely.