Jaspar in a sidepull goes whoo hooo! I can do whatever I want! which for him means unlimited snacking on the trail instead of paying attention. Iguess if you had a horse that wanted to do something other than unlimited snacking it could be a real problem...
I am a believer that anytime you go to something less "severe" you should be really careful... I knew a seemingly really well trained obedient dead broke walking horse that had been ridden all his life in a severe long shanked walking horse bit that was sold to someone who put him in a dee ring snaffle and he bolted, became a bolter in fact. But he had been raised and trained and ridden all his life by one man, so I imagine the new owner had some new ways about her that seemed scarey/frustrating/surprising to him, then the new bit... Myt friend delores bought a paso mare that has always been ridden in a harsh shanked spoon bit and she took it off her and put her in a snaffle and she was an uncontrollable maniac. I guess obviously, the horses needed some training along with the new bit so if you want to change to something milder its best to take the time to train. Like Jaspar, I think all horses take advantage. But Tivar was trained to the sidepull and does not take advantage. conversely, the few times I decided to ride him in a bit--- ok, i confess the reason, I wanted to put a PRETTY BRIDLE on him :) and he aggravated me to death clacking and gnawing the bit like he just hated it. So we have to wear his plain sidepull and i am still scheming on how to bling it up.... janice-- yipie tie yie yo