Corrosion
I can confirm the corrosion fear, I'm a victim.
But it partly depends on how and where you store it. I'm in the southeast, lots of heat and humidity. Plus, I work in the garage and must keep the door open to keep it cool, if it sprinkles or rains while I'm working, the spray comes in a good bit. In my case, there was some edge separation on some pieces and moisture got in one way or another.
How would removal of the plastic help? It would've allow the Al to dry instead of fester.
Also, the plastic stays together better and removes easier if removed sooner rather than later.
You have to worry about scratches and corrosive substances if the plastic is removed (like sweat, blood, any other salty stuff) and if you leave the plastic on, you have to worry about corrosion under the plastic and potentially a difficult time removing it later. Pick your poison.