I'm OK with most of the rules for accessible parking but I think the street parking rule is being exploited.  My neighbors parents moved in with them last year.  They bring a third car to the household which would otherwise have a 2 car limit.  While I think they could fit all three cars in their driveway, they have chosen to park one permanently on  the street.  That one displays the permit.  It's ironic that the rules are being used to allow the car to be parked further away.  The parents always walk to the car.   The rules prohibit parking for more than 24 hours in the same spot but no ones going to get a ticket for that unless someone actually complains.  I'm not prepared to do that yet to someone I live beside. 
Whenever it snows, the window gets cleaned to display the  permit and it's left on the street for the plow to drive around.  It ruins a street spot until the next melt. But the worst impact is it encourages others in my neighborhood to also park on the street.