Is it inadvisable to leave your board inflated?

Q: Is it inadvisable to leave your board inflated? Was thinking of strapping it to the roof of my van until I use it next rather than deflating and I floating over and over?

A: No, it’s best to deflate it after each use. Well…. Actually it’s best to release the overall pressure ! Whether that’s leaving a little air in it ? But then that defeats the object of your idea.

The reasoning behind this is, inside blow up boards there's millions of strands of plastic like string that stops the board going round like a balloon, if you leave the board under constant pressure, there’s a chance your over stretch those strands.
Especially if you leave it out in the sun. 
Blow up boards do have a shelf life, so do everything to reduce its demise.
Def don’t leave it strapped to the roof in the sun