Goodgrief - experiencing mast bumping due to aggressive handling when NOE (which was the main problem in the US military) is not the same as just encountering turbulence or slightly exceeding VNE in a robbie.
Lonewolf - you don't need a vigorous push over to experience it - any unloading of the G, even an entry to auto without aft cyclic to load the disc - can cause it.
As G is reduced, the only thing producing thrust relative to the airframe is the TR which produces yaw and roll that, if there is any untoward movement of the cyclic, will usually cause the MR to chop off the tail. In extreme cases the strain can demolish the pitch change arms as well resulting in even more extreme rotor strikes (like the front of the skids in one fairly recent crash)