As far as I know it is actually meant for all (live) tournament play. I don't think you'll ever see this enforced online unless possibly if there is evidence and someone calls a moderator (though I doubt that as well). I don't know if they'd enforce it at a cash game because of several factors.
And that was the point being made that if she was truely clueless about having the nuts and they believed her, then the TD is not required to give her a penalty. The penalty is for softplay and if he didn't think she was doing that then she'd not likely have gotten the penalty.
If she actually knew the rule and "looked suitably patronized" for having it explained to her, then she's guilty and deserves the penalty. Had she honestly looked like a deer in the headlights as he explained what was wrong and why, then she'd probably have gotten off with a warning.
While the rule may be meant for all play, online makes the distinction, and for the reasons the rule was probably meant to enforce in the first place - collusion. Just because the rule was extended to MTTs doesn't mean it wasn't created w/cash tables and STTs in mind.
I cannot buy hook ladder and sinker some reporter's assessment that the woman looked 'suitably patronized'. She could have been confused, trying not to look stupid or like a noob, or simply to embarassed for her own bad play or not realizing she had the nuts. Maybe even just a super-tight player, satisfied to get the pot as is. Who knows. A couple months ago, I had AA and flopped an A88, nut boat, only to get beat by quads, and I was gone.
Also, we really don't know what the TD would have done. It's probably not written in stone exactly what 'look' or 'response' averts a penalty.
Bottom line, this is the WSOP, you pay 10k to get in. How likely was there collusion? I'd be surprised if there
ever was any in a tourney of this size and magnitude. Even checking strategies for saving a short-stack in unusual situations - it is still not collusion. Maybe rules are made for a reason, but if you can avoid consequences with a 'deer in the headlights' response, what is the rule worth? The rule should be suspended for a tournament like this, IMHO, the reason: common sense.