Kind of a funny one this... When shopping for insurance last time out, I found the quotes could actually get lower when declaring that the windows were tinted. Work that one out!
In any event, I don't declare my tints or anything else I've done to my car. As far as I'm concerned I haven't changed anything that would warrant claiming extra for. ie: I have different wheels than it came with stock, but they are still LEXUS ones, and exactly the same size and spec.
If I was slammed on coilovers, had a set of £2K+ JDM wheels, or had upsized to 19" or something, then yes of course I would declare that (and did, when I had ISF wheels on a few years ago).
But if one of my windows gets smashed in a bump, or by a thief I wouldn't be expecting the cost of re-tinting the glass to be met by the insurance company.
If painting calipers is considered an "offence" in the insurers eyes, I would guess there are literally hundreds of thousands of uninsured cars on the road today.