I think all knowledgeable horse people, understand that any and all horses, 'can' be dangerous. This includes incredibly well-trained animals.
The problem with Minis, is that there are hundreds and thousands, being bred indiscriminately and owned by people who do indeed treat them as only 'pets' and spoil them. And it IS easy to spoil these little ones. This especially when they are really small and still babies. A friend of mine who is incredibly knowledgeable in Minis, recently had her arm broken, when handling one of her pretty well trained stallions. Little or not, they can still do harm and even when well trained.
The majority of us, will probably not see well trained Minis. Most will be backyard pets with little or no handling, after the owners became bored with them or those dear little pets, started acting up as adults. That, or we see them in auctions for a couple of dollars.
A word about bringing Minis into the house. Well my granddaughter has a Minis who does come into the house to watch TV with the kids. But, he is well trained, knows his manners and is a good boy. He is also gelded and has been shown a lot. At the moment, he really is a pet, just as all our animals should be. He doesn't have to do much these days, except being company for other animals on the farm, or for my granddaughters. That said, my daughter has found her front room full of Gypsy Horses at times, when the front door was left open, helping themselves to fruit in the bowl on the coffee table!