For those thinking ‘murica about this… a very common occurrence in the UK are farmers taking pot shots at the insulator strings. Thing is, when one goes in to fix them afterwards they can get compensation for us having to enter their land.
Another unintended problem are polymeric insulators (as opposed to glass or porcelain) where rather than breaking, lead shot embeds itself in the insulator. The damage can be less than obvious and form a nasty flashover risk.
A/c because employed in one of the few orgs that deals with said things.