You can, but it's more effective to show them in ways that do invade their privacy, so in the race to the profit (which is as unavoidable as races to the bottom

You can, but it's more effective to show them in ways that do invade their privacy, so in the race to the profit (which is as unavoidable as races to the bottom), that's what every eyeball agency, lead by Google and Facebook, does. Unless this is curbed by regulation, which I think is extremely unlikely for the next 10 years at least, you can safely assume, and should assume, that all ads are privacy invading.