Not relevant? Of course it is.Just as similar facts would be relevant in a car accident.Driver "A" was sober as a judge and driver "B" wasn't...very powerful stuff.
You apparently don't know many judges.
Apart from that, it isn't the same. The design of the tiger pen was such that it could get out. That is true whether the guy was drunk; or not.
As for your accident example. If one driver is legally drunk, it does not necessarily mean he was at fault. I a drunk is driving through a green light at the speed limit and a sober driver who is not paying attention approaches from the opposite direction and attempts a left turn, who is at fault? The sober guy; of course.