Bad news, glad you are recovering.
I worked at a garage many years ago and our Tecalemit 4-poster used to slowly creep down.
You didn't notice it for quite a while until you realised you were stood under a car with bent knees.
When we packed up for the day we used to lock all the customers' cars inside. One was always parked under the 4-poster which was then propped up with bits of tubing.