Well, unlike with tracking pixels, you are not in the direct request path and cannot block it. You also have no way monitor/log if it is happening (like you can

Well, unlike with tracking pixels, you are not in the direct request path and cannot block it. You also have no way monitor/log if it is happening (like you can in theory with a packet capture). It's obvious in hindsight, but I bet no one would have mentioned this possibility as why you should disable notification previews or that simply receiving a notification would possibly reveal this information.