Nothing is dangerous at all in this whole world as long as you know and follow each rule to a t all the time.
"Danger" defined as that just doesn't exist.
But then there is risk, and there are humans, and human error, and anything that requires more knowledge and pushes more considerations and decisions into the human in a way that it might be possible to forget doing something right is more error prone, more error prone means more risk, something risky is IMHO dangerous.
That is what I would define as "danger".