To say that horses are accident prone anyway and thousands go without accident all the time is a bit like saying cars are dangerous and many people still drive them unscathed, so I guess I just won't wear my seat belt.
If you knew something was safer, wouldn't you just do it?.
Your odds are better if you look after your fences, whatever kind they are.
Your odds are better if you call a vet to attend an injured horse and treat it right from the get go.
I guess that we all do the best we can, but I for one cannot afford to fence all my horse pastures in anything other than wire at the moment, but then again I have larger than average paddocks.
Personally I would choose to have post and rails everywhere, but that is not happening any time soon. I hate and detest plain wire with a passion, much prefer well kept barb to it.