I'm basically on board with this, although for me, with a little nuance.
I see two kinds of extreme tickle torture. One where the person may be freaking out, screaming and jerking uncontrollably, and truly wants you to stop, but because of the nature of the relationship with the 'ler, they understand that they won't later be killed, raped or permanently injured. That's one kind of non-con.
Then there's the other, where they are really fearing that the next development could be violence. That's the kind I'm not okay with.
But it's a pretty safe bet that if the 'ler is a boyfriend, husband, sibling or friend of the 'lee -- or even if the 'ler is just someone who doesn't seem to have a creepy personality -- the 'lee probably isn't going to be fearing violence. They'll know it's only going to tickle. For me, that's a huge difference in these extreme tickling situations that the usual non-con debates ignore.