I think they definitely are cleverer than most think. I remember my sister being persona non grata at Pony club to a degree because other girls were reluctant to partner with her. She could always manage their horses, but they always had great difficulty with hers - it didn't like people who didn't know what they were doing...
Kelly was very careful and patient with people who were genuinely nervous first-timers, with the Down's Syndrome lasses at RDA - some of whom were very capable, but many very much less so - and with the other attendees at RDA, many of whom were seriously, and multiply, handicapped in a range of ways.
I was once on a long leisurely ride and stopped at an ice-cream van in a car-park in the Peak District; a gentleman came up to me and asked if I could possibly take my horse to the end of the car-park as his disabled daughter was in the car and absolutely loved to see a horse so of course I did. The young woman was in a wheelchair in the back of an adapted car/van and was clearly excited at the approach of a horse; I said to the gentleman and his wife that Kelly would be absolutely fine if their daughter wanted to come out of the car, a wheelchair wouldn't bother her in the slightest. So they let the ramp down, wheeled out the young woman and Kelly nuzzled her in a very gentle way, while the young woman giggled in pleasure and excitement. Her parents took photos, they were so touched and said they'd never thought it possible that their daughter would get so close to a 'proper horse'.
My relative's step-daughter
thought she could ride; Kelly gave her the benefit of the doubt initially, but when the doubt was erased ... I honestly think that if the step-daughter had just given up and clung on, Kelly would have plodded slowly back home being careful not to unseat her. She certainly used to do an imitation of 'the safest way to carry a Dresden China doll' whenever she had an unfamiliar rider at RDA!
Yet she was a great dramatic actress in the best tradition of Arab horses; tail in the air she would arch her neck, toss her 3ft long mane and dilate her nostrils until they glowed blood-red while snorting ... really quite scary for ramblers who were abusing the two lads who used to come out on their mountain bikes with me ...