I am going by what I read concerning the BRS as for the 800 foot minimum,..as for quote" How aobut a prop breaking and ripping the engine from the plane, rendering it unflyable,end quote" ..I would classify that as structural failure,..
I never said a BRS wasn't a good thing,..I've owned a few planes/ultralights with BRS's in them ..never had to use one (knocks on wood) didn't get a warm and fuzzy feeling because it was on the plane ..but you can bet if I had structural failure I'd be pulling the rip chord no matter what the altitude if there was a BRS on board ..there is always the chance you will get lucky and the deployment will open the canopy to full ,..short of the 800 foot altitude that's recommended for deployment,..maybe the manufacturers listed the 800 foot altitude because they had to present a number?

Chase