A limit of 220 is still very alarming, considering the average height for men around the world is 5'9". (Source: healthline.com) A weight of 220 would be an average BMI of 32.5 (obese). While many tourists would be over 5'9", and therefore be better weight distributed, many would be shorter, and even more of a sack-of-potatoes for these poor beasts (the donkeys, I mean). Unfortunately, these tour-guides won't do anything more than legally necessary to fix a problem like this because it would mean less profit overall.