On the flip side, maybe they decided it would be more rude to try it and gag on it than to politely decline. If I were the squeamish type (which I'm not; I'll eat almost anything), I'm not sure how I'd handle it. On the one hand, it may be considered impolite to order something other than what everyone else is eating (although if they were serving other dishes besides haggis, I'm not sure why it would be rude; that's what a menu is for). But trying something you know might make you need to spit it out in front of the hosts before you vomit might be the worse option.