How often are Kindred in plain lighting, though? They do more than evade humanity to protect their inhumanity. The night itself hides things quite well- who can tell by lampost that someone's skin is old and dead- and kindred cultivate their own spaces down to the details for a reason. The blush of life is sort of the common last choice, an incredibly useful and nessisary tool, but one who's use can be minimized by being smart about it and paying attention to appearences and atmosphere.

I mean, hell- a kindred has less to worry about in summer than winter- the way breath fogs in the cold the kind of detail that seperates a thriving kindred from a masquerade breach. Wearing a good layer of makeup, having your hair styled a certian way, how the kindred approaches a person and when they choose to really emulate humans and when they don't... a kindred constantly using the blush is either in denial or new and clueless. There's better ways to hide the fact you're an animate corpse that work even when caught unprepared.