I've seen both ends of it. I've watched a small handful of people with other backgrounds who picked up this falling stuff almost instantly. If I remember correctly they were a mixture of wrestling and shotokan. But the fact that they stand out says something.
On the other end of the spectrum was a shared situation I was in where the main part of the school was Tae Kwon Do. They just didn't get why we were disconcerted with concrete covered by rubber. The owner was certain he knew how to fall and that it would be fine for us (like he does koshi). All I know was that while watching one of his instructors teach a beginner to fall I had to leave because the instruction consisted of "just roll". I was probably the most scared person in the room and someone else looked terrified.
And I don't care what anyone says about falling on concrete. It hurts like hell.