In my Hapkido dojang we also simulate the throws. Being a white belt, I've only learned one throw, but it's one that really couldn't be practiced safely since the intent of the throw is to have the "throwee" land on their head instead of their back. I'm not sure if other Hapkido throws are done with this same intent, but if so, it would make it much harder to actually practice throwing. I have taken a couple of classes of judo so I know what it's like to be thrown. It can be fairly dangerous if a person doesn't know what their doing. I had the misfortunate of someone throwing me, then tripping and landing shoulder-first on my head. I imagine some schools don't want to actually practice the throws for insurance reasons.