Thought this was a clever construction trick. A street nearby my house had some construction work scheduled. During the construction, the normally two-way street would be made one-way for several weeks.
In order to communicate this quickly, the city put up “One way” signs but then covered them up with plastic bags at first. When they were ready to restrict traffic along the length of the street, they simply removed the plastic bags.
It made me think of commenting out lines of code – then uncommenting them when ready.