As others have said, if you don't try to cut with the spine, stab, peg, use as a screwdriver, etcetera, you'll have no problems. The normal cutting action forces the blade open - not closed.
As for "hard use" ... how about building a thatched survival shelter?
Vinnie's Day Off
The knife looks like a "half congress", in the 3.5 inch closed range.
(If you pay attention, you'll learn how to easily fell saplings without chopping or batoning.)



I've watched some of the Vinnie's day off videos, and even though I I am a slip joint enthusiast, I still find it entertaining. It should be required viewing for those who think a knife needs a lock that can suspend a Brinks armored car.