I remember long time ago doing VMC demos, 5000ft being the lowest allowable height.
The official height limit is 3000 ft. But most POH's in small twins explicitly say 5000 ft. The problem is that the aircraft will then stall if you insist on full rudder deflection doing a VMC demo.
Ludicrous exercise that was eventually stopped after a few crashes
Given this accident wouldn't call it a ludicrous exercise, unless of course you're referring to a potentially unsafe altitude to conduct it.