The worming only happens if there's a coating over the finish. It isn't exclusive to clear coating but obviously shows more that if it was a colour.
If you leave it bare or polished thwn you still get the oxidising but it happens evenly and first appears as a dulling of the finish then starts feeling rough and eventually giving of a black dust as you handle it.
You could do this for years as it happens quite slowly.
This is why most silver alloy frames are actually ball burnished or brushed as this gives a shiny appearance but still allows a coat to key.
I've always found re polishing to be a pain on anything thats built up as you can't get into all the nooks etc.
Never tried clear plasticote but have used the coloured stuff and found you can peel it off quite easy so I'm guessing it doesn't stick, meaning any chips will allow moisture in.
You could still try it though sometimes the real world is the only place to get difinitive answers.
97 Marin Nailtrial