To get transparency in the AS 350, the manouevers are so severe that you could fly without ever experiencing it, i have had it demonstrated and as one of the other posters said,it is quite a deal to set it up, I don't see it as a design flaw, it was designed at the time with the technology available, its an excellent aircraft and an absolutely stable platform to work from. Ive flown up to and including the B2, i havn't seen or read the B3 data, but if it was a serious concern, the B3 may have changed.
Anyone who operates an As 350 outside the performance specs and limitations is asking for trouble, doing anything, its a light helicopter with limits, the manufacturer has identified them for the pilot, fairly straightforward.
It is an extremely violent manoeuver to get to transparency. I have only had it when its demonstrated, never encountered it in normal ops or had other pilots experience it in normal ops.