A yokel told me that the blue painter's tape can be permanent. He heard of someone leaving it on the window pane too long ( like a year ) and it turned the glass blue. Is there any merit to this yokel?
Glass is inert and impermeable, so no merit to the yokel's claim that it turned the glass blue.
That said, like most tape, it can dry out and leave a residue over time. Which can typically be easily scraped off.