How far does this line of thinking extend? What about small startups that work out of someone's house or apartment? They're doing commercial activity in an unzoned area, so that should be banned too.
How about coffee shops? Coffee shops are generally licensed to sell coffee and non-cooked (on premises) goods. Want to sell sandwiches made on site? That's a different (expensive) license. Beer and wine? Same thing. So coffee shops aren't licensed to be places of business for customers to perform commercial activity. We should ban engineers working from cafes too.
I've always liked the petition (http://bastiat.org/en/petition.html) Bastiat sent to the French Parliament proposing that they block out the sun to benefit French candle makers. Its in the same vein as a Modest Proposal from Swift about the Irish poor.
We're seeing government protectionism of new competing services against established and entrenched businesses, i.e. taxi medallions vs Uber/Lyft, hotels vs Airbnb, city-built fiber vs Comcast/Time Warner.
This is dangerous. It limits competition and competition is almost always good for customers.
We need to stop this from happening in SF.