I prefer to wake up manually my Spectre x360 every time, even if I open the lid. The reason seems obvious to me: although the building quality is among the bests I still want to be 100% sure that the laptop won't start accidentally when carrying it e.g. in a laptop bag.
On older (?) HP laptops there was an option in BIOS→Boot options as “Power On When Lid is Opened” which could be deselected. But I can't find this option in my new Spectre x360 anymore.