Bleh, new posts reminded me of this thread. Depending on the use of the knife, general use or defensive, you may want to consider a kydex sheath that holds it open, or even one that holds it closed on your hip. Not trying to be tacticool, but it's an option that others have used.
I have a CRKT Heiho and have, fortunately, never had this issue. An old friend did once, simply because the knife was too sensitive and was tip down. It takes time to retrain for a tip up knife but it may be a consideration....
Though, you sound like you've found your ideal carry...
"Today is victory over yourself of yesterday; tomorrow is your victory over lesser men." - Miyamoto Musashi
[Insert random irrelevant religious quote here]