Ok, let’s take the in store analogy. Agree that following someone home to spy on them is wrong. But in store, if I see a person looking at some items on a shelf and start to tell them about related items, doesn’t that violate the need for explicit consent? Expecting “full understanding” is too high a bar, IMO. Implicit consent, public notice and opt out are sufficient. Otherwise you end up with GDPR cookie opt ins that only train people to indiscriminately push “accept” buttons.