Never heard of this happening. It's weird anyway because roofs are something you're expected to maintain and are pro-rated. If you have storm damage to a 20 year old roof, your insurance is only going to pay for the estimated remaining life, not the full cost of a new roof.

If the roof is beyond end-of-life they probably won't pay anything, as it's a predictable cost of owning a home not an unexpected loss which is what insurance is for. Same reason they won't pay to have a tree taken down just because it could fall and cause damage. You're supposed to maintain your property; insurance is for losses beyond normal wear and tear/maintenance expense.