Precisely as Micca said. Cattle stealing, raids and clan feuds were practically a league sport back then (or so my reading seems to suggest). What made the Glencoe incident so infamous was the base violation of the rules of hospitality. I'm told that even today there are highland pubs that still have signs up saying, "No Campbells Allowed".

On a lighter note, one performer I saw said that he could never quite get it all straight. Was it the Campbells whp made soup out of the MacDonalds or did the MacDonalds make hamburger out of the Campbells?