there is two points to note in this discussion.
1) The Rotax units are all (normally!) equipped with electric starters. Given a decent battery, good heavy cabling and a following wind they will turn over at a good rate and start well. The mags will not even think about creating sparks at the speed used for the "oil gurgle" activity.
2) Many Lyconentals have an impulsing mechanism which is designed to give a good healthy spark at very slow engine rpm and thus enable easier hand prop starting or electric starting if the battery is below par.
So the level of danger at the noisy end is related to the type of engine you have, up to the point that it starts running and then all are dangerous.
Also, I note, a number of posters saying that they always make sure that the master switch is off before venturing near their propellers. Why? the master has absolutely no influence over the ability of the mags to generate sparks or the engine to run. The only difference is that having the master key in your pocket will stop a naughty passenger operating the electric starter.
Rans6.....