I have also had a tip up finger slice but it was with a Kershaw Leek which was a spring assisted opener. I had it in my back pocket and must have sat in the flipper lever. I sold all my assisted openers and have not had a problem since. This Massdrop Gent will not open as it has a ball detent keeping the blade securely closed.
As for tip up/tip down carry it comes down to what you get used to. My Spyderco's are all tip down and others are tip up and I really don't have to think before I deploy either of them. Understand they are not fighting knives, they are opening packages.
As for full auto's accidentally opening, many of the really good ones will stop themselves if encounter resistance before fully open.
"Never pet a burning dog"
Out the Front automatic knives come in two styles - single action and double action. Double action OTF knives snap both in and out with the button. A single action OTF knife snaps out but must be manually retracted. The springs on a double action OTF are not very strong and if the blade encounters resistance will stop it before it reaches lock up. The manually cocked spring on a single action OTF can be significantly stronger and penetrate deeper. If you like to play with your knife, the double action OTF is a lot more fun.
I carry a Kershaw on a clip, tip down. I feel it is very vulnerable to drop age as I pull it from my pocket with mu thumb and first finger and then spin it into my palm to flick it open.
In my opinion, the Kershaw spring assisted openers are very vulnerable to accidental opening whether tip up or tip down, in fact, I once dropped my Leek and it opened on impact. Yes, there is safety lock but I found it to be very inconvenient thus my reason for selling them. All I have left are Spyderco's and a couple of oddballs that are currently all manual openers set up for tip down carry.
After Benchmade's screwup, I debated on cutting it in half and sending it back but then realized that would be doing the same thing they had done. I thought even though I had an axe to grind with Benchmade, not all people feel the same way so, I put it on e-bay and the current bid is more than I paid for it pre-owned. Go figure.
"Never pet a burning dog"