just checking late on this thread. not sure why it's so emotional.
I understand cracklovers set of circumstances. strange things could happen to a pair of biners if they are protruding over an edge like that.
but practically - that type of set-up is a safety violation. a TR should NEVER be set up so the biners just poke over the top of the rock. the biners should always hang loose and free - beyond the edge.
i'll leave it to people to debate the in's and out's of the argument. cracklover's scenario simply reinforces that the age-old safety standards are true - if you don't use bad set-ups with your hardware - you don't get bad results.
BTW - I always used oval biners for TR's, and generally preferred locking biners anyway. if I used the oval biners, I usually set it up as 3 biners (not two), with the middle opposed to the two outer ones. the reason for choosing oval biners is that D-biners can do slightly odd things, just like cracklover showed - they are a bit more prone to working their way inside of each other.
It's so emotional because a certain percentage of rc posters live there entire life mitigating against "what if" events, no matter how remote or unlikely the occurrence of a given event. Underlying this is the misinformed and breathtakingly naive idea that risk in rock climbing can be reduced to zero.