When I saw this ad I was not concerned about the little girl riding her BUT more about the contents of the ad.
I don't think any 'horse person' goes looking in a catalog like this to find a mini for their child.
This catalog, is appealing to affluent city type people with little knowledge of animals other than perhaps a house dog. Although the picture is very appealing I would worry about the horse being considered a toy.
I have first hand experience with this, I live in a fairly affluent town and many people want to "get one" of my little minis for their darlings! BUT they have no idea about how to take care of it!
Last year a lady who had called me over a dozen times about my little colt and she sounded like a great home, nice barn etc, lovely lady, nice kids etc!
When she came out to see him, I let him out in the field to run, she said "oh, they like to run??" Then I asked her if she would like to walk him, she said "Oh no, I don't think so!" She called me that night and said she felt foolish but she had not realised it was really a horse she had considered it to be more like a "toy" or a "Lawn ornament", she said she did not think they could handle him! He was a 5 month old 29" colt, gentle and sweet!!
So that would be my concern, if it were my horse, that non horsey people like how it looks but really have no idea that it is not "lawn ornament" and really does need to be cared for.
I just hate to see live animals sold as novelties, it does not normally end up well for the horse. IMO an animal that can live for 30 years should not be advertised as a fun novelty. Can you make money doing it, You betcha!!!