Enclosing the Commons

According to the Strib, the City of Minneapolis is trying to keep strangers out of alleys:A back-alley approach to fight crime in Minneapolis. The alleys will essentially become private streets for the residents.
From the article ‘”If you don’t live there on that block there’s no reason to be in the alley,” said Killebrew, who proposed the ordinance to the city attorney.’
Well I can think of reasons, namely taking a walk and looking at the backs of houses, which provides lots of entertainment for law-abiding folks in the summer, doubling the amount of entertainment that can be had from simply looking at the fronts of houses.
I just don’t understand how this is supposed to help. If you have already broken the law (or intend to), the alley ordinance doesn’t seem like much of a disincentive. Neighbors might now report more suspicious activity (where “strangers” in the alley are suspicious), but nosy neighbors are pretty good at that in Minneapolis already.
See enclosure and private road.