Hobby Horse competitons have been a thing in Finland for a bit now, with reportedly over 10,000 youths participating.
It is so big that at the 2018 World Equestrian Games at the Tryon International Eqeustrian Center in Tyron, NC there will be an official Hobby Horse Competition.
The competion offers different fence heights for jumps and tests/levels for dressage riders. There are also awards for Best Hobby Horse and Best Stable. We needed to see video of this to fully believe it.