I was kicked at my first show (the county fair in 2002) by a mini mare in heat. An unfamiliar gelding got too close to her and she let fly, catching my knee.
I was kicked one time in the side of the leg by a young filly who I was helping control while her hooves were being trimmed.
I was kicked in the leg by my own gelding (stallion at the time) while I was leading him to the arena. He saw a mare in heat, then another stallion in a nearby field. He sidekicked me leaving a nice black buise.
I narrowly, and I do mean NARROWLY, missed being kicked in the head one time. I was helping load a mare into a trailer and she was refusing. In her frustration, she kicked out with both hind legs. As a reflex, I step to the side and raised my arm. Her cannon bone hit my forearm, leaving her hoof mere inches from my face. I'm about 5'4" so you can just imagine how high that kick was.
My friend was kicked one time while giving her filly a bath for the first time ever. She got it right in the knee.
That same friend also got kicked again in the knee this last year by my gelding (stallion at the time) right after his first show.
Plus I'm sure there have been numerous other knicks and scratches between the both of us that were so minor we have forgotten.
Depending on where you get kicked, yes it hurts. Minis might be little, but they can do some damage as far as causing pain and breaking bones. Those back legs can let loose at a moments notice and are quicker than lightning. You best bet is to keep a close eye out and prevent a situation where a horse might kick.
Erin