It's against ToS to intentionally do, but Bungie and your respective service provider would not ban you for it, as it's too hard to prove exactly from where the network issue had arisen. Sure it will look odd that it seems to happen all of the time during the Crota fight, but, as I've had countless raid members suddenly DC to some stupid error code, or having the Destiny game bug out, and shut down completely. They have no way to prove intentions, unless you're writing about it all over the place. Edit: "I know a guy who got banned for this cause they said he broke ToS" isn't proof that anyone's been banned at all hah.