This is one of "those topics" that always sets off a firestorm of emotional outbursts. One school shouts, "DON'T GET OUT!" while another says, "Eh, what's the big deal?"
As Gordy points out, the U.S. FAA doesn't seem to have a problem with it. They've even issued one of those non-binding Advisory Circulars about how to do it "safely" (AC91-32b which still uses images of a Bell 47J so that tells you how old it is).
Anecdotally, we hear horror stories...some awfully questionable...like the one about a person who threw himself over a skid to stop a sliding Bolkow? Uhhh...not! Once a mighty Bo105 gets sliding, no mere mortal is going to stop it. If it stopped, it stopped on its own.
Then someone mentioned an AB206 that got blown off an oil platform in...what?...1968? Oh, how timely! Haven't we had a more recent example than that?
Look, getting out of a running helicopter is not dangerous in and of itself. In all my years of flying helicopters for money (28 so far), I've never been in one on the ground at idle rpm that did anything wierd that I could do anything about other than hang on. And I worked for PHI offshore for 13 years. I've never had one catch on fire or blow up. The controls are ineffective at idle.
Legal or not in your particular country, the problem with "getting out while running" is that it requires common sense. And that is something that is strangely lacking among our peer pilot group, evidently. Common sense items would include (but are not limited to):
IDLE RPM!
Light winds
IDLE RPM!
Stable surface
IDLE RPM!
Controls frictioned
IDLE RPM!
Low likelihood of a Chinook or Skycrane landing next to you
Seems simple enough, no? If you cannot vouch for all of the above, don't get out! Shut down. Alas, we are not as a group known for 100% expert judgment, as evidenced by the continuation of accidents as time marches on.
My helicopter has components that are cycle- as well as hour life-limited. In fact, it's a toss-up as to whether my #1 and #2 wheels time-out or cycle-out first. It is patently absurd to suggest that my passengers will -every time, mind you- sit through a complete two-minute cooldown and then rotor coastdown to a stop (no rotor brake). Me? I get out when it's appropriate. I take all the precautions, and I don't think that I'm doing anything horribly unsafe or even needlessly risky. I know that idling helicopters do not spontaneously explode or roll over on their own. But passengers do walk into tail rotors. Seen that happen once for real. Wasn't pretty, is all I'll say.
Obviously, others will have an opposing viewpoint. And that's cool. The debate rages on...