Smart Cars are intended to be the ultimate in convenience for driving and parking in big cities. Many people use the small vehicles for their daily commute, and take advantage of the fact that they can fit almost anywhere. There's no need to take up a whole parking space when your car's so small that it can just perch on the end of a full row! Not all spaces are available to Smart Cars though; especially when clearly indicated otherwise.
The downside of a Smart Car being so small is that it's really easy for someone else to make it a little wooden prison, like this one. We don't know if the owners of the painting and decorating fan just happened to be there by chance, or if someone specifically called them out to do this job. Either way, they've gone the extra mile with their work. We imagine that the wooden frame could be lifted out of the way with a little effort - but not without everyone noticing you first.