I think you may be missing what an "obvious" shot is under CSI rules. It's possible for an entire match to be played with no ball ever explicitly called.
I haven't seen the CSI rules. I will say that I have never played ten ball under rules that didn't require calling the ten. Not saying we called the ten, most of the time we didn't even shoot it, but we were comparatively small groups and comfortable with not making a big deal over nitpicking things like straight in money balls.
As you pointed out earlier, there is a list of "not obvious" shots by rule. That is what caught the young lady as we both no doubt recognize. The shot was obvious and any other option almost impossible. Under most circumstances, we would all be fine with the no-call, as many have said maybe mention it between games.
Some of these rules and regulations seem silly but the line has to be drawn somewhere. I understand that, I still have a couple questions in my mind. Might as well stay there and fill up some loose spaces!
Hu