why do horse polo players put so many 'gadgets' on their horses?

sorry im not sure of the correct name for 'horse polo'... but anyway... why do they cover their horses head to toe in gadgets, i know some are useful, like breastplates so that the saddle doesn't slip back, but they make them wear so many things and then use them to cover up bad riding..

http://i.thisislondon.co.uk/i/pix/2009/04/polo-player-415x538.jpg

shes got some pretty harsh 'gadgets' and bit arrangements going on and then shes pulls back on the poor horses mouth, causing him visible pain. a girl i know at school plays 'horse polo' and a few months back she fell off her horse, which resulted in her fracturing her horses jaw, as she kept hold of the reigns when she fell, and her weight (shes only about 8 stone) combined with gadgets and harsh bits to 'control' her horse fractured it, and she didn't really seem that bothered- if i had done that i would be disgusted with myself. i know accidents happen but that's just awful!

why do they do this? i just don't understand?! people say horse racing is cruel but this to me is much, much worse. i know they aren't all like that but what happened to the days when it was about the skill and partnership of both horse and rider?

here's another pic of some horse polo...

http://www.bournemouthecho.co.uk/resources/images/368480/?type=display
*sigh*.... Bailey- i know what they are all for.. i havent been around horses for 13 years without learning anything... jeez... what i want to know is why do they use the gadgets to make up for bad riding, not what they gadgets are for.
Julie - i may not be an expert on polo, but i do know that the woman- whatever happened before- should not be ripping about on the horses mouth like that. if she is trying to gain control of her horse, she should be using her hands aids ALONG with seat and legs, which she is failing to do. i know that breaking a horses jaw can happen with any bit, but its the way she reacted- like it happened all the time. and your saying only the worst parts about racing, some of which are not true, many good racing stables work their horses fairly and give them breaks, its only the shitty backyard 'racing' stables that are unfair to their horses, so dont have a go at me if you dont know the extent of my knowlegde- i may not know it all about many disiplines, buts im not stupid. and yes there are 'evils' in every disciplines, but that doesnt give people the right to treat their horses badly.