I've used false grip exclusively for over 5 years now and don't think I could go back. Have gone over 400 in competition with that grip and bit higher in training.
Never thought twice about it until last fall. Tweaked my pec and moved my grip in a bit and touch point a bit lower as it allowed me to bench pain free. On the third day with that grip I was benching 385 and had it about half way up with good speed and the next second it was bouncing off the safties in the rack, which luckily could be set at 1 inch increments and I had them set correctly and the bar just crazed me just below the sternum.
It happened so quickly I had no idea what caused it. I had it videoed and it showed me getting just a bit out of the groove and my wrists shifted forward slightly to get back into proper position and that was it, bar came right off the meaty pads on my hands which is where I hold it (directly above the wrists).
Haven't had an issue since but other than during a meet I bench exclusively in my rack with the safties set at the right height. A rear spotter has zero chance if you lose it. Even two good size side spotters aren't likely to stop the bar before it hits your chest with at or near 400 on it when it goes into free fall.
One thing I will say is by holding the bar on the pads of your hand directly above your wrists if you lose it you are going to lose it moving forward and crash into your chest or upper abs not which isn't good but is a hell of a lot better than landing squarely on your neck.