Ther are an awful lot of bad sellers but also bad buyers! In the past I have had to rescue people who had not even tried the horse they bought or bought one because it walked down a road with her without being on a leadrein. Buyer beware but buyer also needs to be honest and take an advisor.
Even the most savvy buyer can get into problems. I recount to many people the attempt I made to buy my daughter a 21st present of a special horse, despite me describing my needs in detail ( talented daughter then at university so had to be safe for not very strong me to handle on a daily basis and to go a few days without work). Arrived to see horse who proceeded to cart 6'3 fit man down yard and then when we said 'not for us' were asked to watch him ride. agreed the horse had talent in spades when it occasionally had four legs on the ground, rider commented he hadn't had time to ride the day before. We made our excuses and left,no doubt being describe as 'timewasters'!! Went and bought her a car and a 'cheap' ex racer ( for less total money than the first horse!) who she retrained and qualified for all sorts of national competitions from sidesaddle to WH/SJ