I dunno, for sure guillotines put pressure on your neck. It's not as dangerous or sudden, but certainly someone going 100% in contest can make something happen. Not to mention size disparity. Heck, I thought my face was going to get crushed under one big white belt's failed guillotine. Plus, having a neck injury, I often get pain whenever put there. Sometimes I can even feel something shift. I don't mind it being banned in Judo but okay in BJJ. Let's face it... people in Judo generally are less precise in newaza technique but go 100%.