2 Hour Parking Rules

Near my university there is a residential area with free 2 hour parking along one side of the road and also in an alley way. The alley way behind the back of a church and houses. One of the houses has a “No Parking” sign with a tow image.

Just wondering if that sign is at all enforceable? The alley is public parking I’m sure, so as long as we only park for 2 hours I should be okay right?

Even if the city comes they’ll mark my car for 2 hours then tow right?