I think one can only do what one can do, so to speak. Unfortunately there will always be people who take silly risks. A woman near us continuously flouted the foot and mouth restrictions and snuck into the inclosures near us, until someone reported her. (No idea who, really I don't, not a clue, no Guv, wasn't me) She could have killed off a dozen horses or more, just by selfishness.
While the woman was irresponsible to ignore restrictions you needn't have worried about the horses because they aren't affected by foot & mouth.