I imagine brooms would work much like wands do. They are magical objects in and of themselves, but they require a witch or wizard who can use their own magic as a channel in order to use the objects to their full potential. I believe J.K. has said in interviews, were a Muggle to attempt to use a wand, the results could either be miniscule or detrimental (think like in the wand scene in the first movie), but they wouldn't be able to use the object to the same extent that a wizard could.
I would think that if a Muggle were to try and use a broom, either it wouldn't work or it would take off flying without the passager...or with them hanging by three fingers and being dragged through the canopy of a forest or the rooftops of a city. Which do you think would be more painful?
Ooh! Rooftops! *came from Death thread*
It sounds like, in that post, that wizards have magic more apt for controlling the wand, rather than actually channeling their magic to use it. Anyone agree in this theory? I think not. And then we'll get into magical genes and such, but in short, let's just say I believe that wizards have the gene of magic, which means they can perform it from themselves, as per case as magic without wands. Okay. Just wanted to clear that up.
Originally Posted by Molly
As for Muggles on broomsticks, I don't think that the broom works in the same way a wand does, it is more physical than meta-physcial, which is what wands use, because, in theory, they tap inside a person's magical ability to produce physical magic. Since the broom shows no indication of doing this (tapping inside a person for it's power) I would assume that it would work the same for a Muggle, maybe going a little haywire. Because the broom is an enchanted magical object, (that is, it was once a regular broom) it has different properties than a wand. I'd like to think of it as an iPod touch and a camera you improvised to play music. The camera can loose the music-playing file, as the iPod touch cannot, because it is permanently programmed into the device. I'm sure it can be removed in some special way, but it's really meant to play music, isn't it? Compare this to a wand and a broom. You can take the magic out the wand, but you can't take the wand out of the magic. Try to get it, okay?
But getting back to the original topic-- yes, most magic can work on Muggles, again, they didn't perform the magic themselves. Okay. Good.