I'm not thinking of something as dumb as an industrial robot. You would want a safety mechanism that detects nearby humans (say in the same room) and switches

I'm not thinking of something as dumb as an industrial robot. You would want a safety mechanism that detects nearby humans (say in the same room) and switches to low power mode if any are present. That way you can get work done at a reasonable speed when the robot is alone with very little risk of hurting anyone. Yes, there are some safety issues to take into account with a household robot but they pale in comparison to those of a self-driving car whose whole reason for existence is to pilot a > 1 ton metal object at high speeds.