In the real world of common sense, DoC should be no more or less, than taking care to not set someone up, for a fall, injury, or other personal detriment, that could be created by fault on your behalf.
Unfortunately for all of us, smart-ar$e lawyers, intent on huge, fast bucks and personal glory, have commenced manipulating laws and legal systems, to the point, where any personal responsibility is removed from judicial rulings, and madness is the result.
One is expected, via these extremist and unreasonable rulings, to be able to foresee any amount of stupidity on a clients behalf, and one is also expected to take steps to prevent this level of gross stupidity. At some time, somewhere along the line, surely common sense will again prevail in the legal system?