|There might be a risk even if the lion is well trained, but the chance that it'd both do something dangerous and is impossible to stop is rather low.|
I have seen that picture before and absoulutly dissagree with it. Not so much beacause of the predator prey match up but more so because of the most likely methods of bringing those two animals together.
That lion has no teeth. And while cats can eat fine with no teeth I can't honeslty say that lion looks as healthy as it should. I strongly dissagree with animals for entertainment such as that...any circus with animals in it I will have nothing to do with.
And yes simply riding a horse or even owning a horse is unatural for them but as far as I can see owning a animal ( provided its looked after to the best of your ability ) and using animals in such a fashion like in this picture, altering them to suit the act and keeping them in more than unatural conditions don't come into the same catagory.
There is nothing cute, amazing , or whatever word ya wanna use, about such an act. Makes me furious, and I know humans do far worse to animals but that doesnt mean things like in that image are any less worth attention.