These cars are driving on public roads, so the question is not whether the user is informed but whether they are compliant. It doesn't take many ignored beeps to learn that a particular customer is not using the feature as intended, and deactivate it for the safety of others. Offer to turn it back on after watching a trainig video at the dealer and signing some papers once, escalate to a mandatory counselling session after that, third strike and the feature is permanently off. Put it in the TOS so that asshole drivers can't sue and win in court. The customer should not be king when the safety of others is on the line.