Less than a second later, this kid on a bike comes barrelling flat-out down the driveway, sees us, slams on his brakes but was going fast enough that he couldn't actually stop and there was kid and bike flying towards us in a cloud of dust and squealing tires and brakes. The horse continued stepping sideways so as to be out of the way. I nearly jumped out of the saddle and shouted some choice expletives probably not fit for that child's ears. The kid, after he'd emerged from the dust cloud, tore off as fast as he could ride in the opposite direction. Little bugger.
The horse = kid and bike safe. The rider = not so much.