I cheated... I didn't have pop in the house so I improvised with a 12 oz flask of my favourite rum! 
 
 It failed about 50% of the time.  It depended a bit on how I held the sheath.  If held by the outside edges it lifted 10% of the time but if lifted by the sheath tip as in Doug's pictures it lifted 90% of the time!
Also an interesting note - I couldn't find the knife at an REI store in Colorado but I could get it locally in Regina at a knife specialty shop although I had to pay a bit more for it ($35 CDN)