Former neighbor in Mesa AZ had a car backed in his driveway under a cover. It did not stop the code enforcer from walking up his driveway and lifting the cover to verify the tabs were current. Don't know if it was legal or not.....
That sounds kind of "iffy" since it was on private property. If the tires were flat and there was on city ordinance/code that states something about that, then the inspector could site the good ole "probable cause" since it was breaking code. Now if you're in a HOA, then you're probably screwed all around. Most of them can even look over your wall into your back yard and fine you for "discrepencies". I won't live anywhere that has a HOA, but that my personal preference.