P-51 radiator damage while on the ground

[Trilisser]

Is there any data as to how vulnerable (or not) the P-51 radiator was to foreign objects thrown into it by prop while ground running/taxiin/take-off/landing during wartime ops? I recall a Warbirds Worldwide article on filming the "Empire of the Sun" mentioning that during filming some such damage occurred while flying from rougher fields.