Ng wasn't fouled enough to disallow their goal, but fouled enough to give away a penalty, but also wasn't being fouled enough when you could see his shirt being stretched off his back. I watched it on my phone in a subway carpark, and even on an iPhone screen it was clearly visible. Maybe not to the ref, but surely one of the lino's notice? They're there looking for offside so surely they are equally positioned to see fouls like this?