It's weird that you can full-attack when you're grappled

[tylermalan]

Ah yes, that video. Another good example. To throw a "non-groin" example into the mix, I would use Yuki Nakai, a Japanese mixed martial artist who was intentionally (and illegally) eye-gouged so hard in a fight that he permanently lost vision in it. Of course, he won that fight. AND the fight after that, if I remember correctly. Though, this isn't the best example of an illegal technique being ineffective at breaking a hold, but it is rather convincing regarding the efficacy of illegal techniques in general.