I'm thinking if I can walk acrosss water, I should not be setting off pressure traps.
As for exerting force, that isn't the way elocators work. There powers involve space/location, not force.

What makes you think you can walk across water? The spell is Scorn Earth, not Scorn Water. The concept of the magical spells seems to focus on the elemental property of the ground... change that element and it won't work. As a DM I would rule the spell ONLY works over earth.

"While she remains within 1 foot of a flat surface of any solid or liquid, "
That's lets me know that I can walk across liquid.

So you're like a hovercraft, but they cross liquid and can do so by exerting downward force. You just do so buoyantly.

Personally, though, I'd rule against having any effect on the floor. How scornful are you of earth if you still affect the ground as if you weren't scorning it?

Ha. Well put.

Re: flying and move silently. With the notable exception of owls (whose feathers are specifically designed for silence) winged flight is at least as noisy as any form of ground locomotion. This, of course, does not address the issue of magical flight, levitation, and Scorn Earth.

The rules are silent on this point, and I feel like it becomes a severe case of aesthetics vs. mechanics if we're not careful. If you are playing a sky-mage, someone whose spells are thematically related to wind and lightning, it might make sense to have your fly and levitate spells represent winds buoying you aloft. Very noisy. Ahah, but Ms. teleport-happy dimension door-loving Transmutation specialist who deals directly with space/time has no such noisy winds. She should get a Move Silently bonus. Uh oh ... now you're punishing Mr. Sky Mage for his aesthetic decision. Bad idea.

I think the only solution here is to play it by ear. Give circumstance bonuses where called for. If you're trying to sneak across a creaky floor, take your +2-+4 bonus. If you're trying to sneak through a room filled with bells on ropes (or a glass-beaded curtain, to use a less far-fetched example), you get no special boost.

As far as jumping. It seems clear to me that when you're 1' above the ground, you are functionally standing and can do anything you could do while standing. While higher than that, you are levitating and no longer able to jump, for example.

As for the style, I think the not-having-to-move-the-legs bit is cooler, but that's a purely aesthetic decision and you should be free to do whichever you prefer.

You're not punishing the sky mage if your campaign doesn't have a sky mage. And if it does have one but not a dealer-in-spaces-and-times, the sky mage doesn't have to know you'd give the other school of thought a move silently bonus, and thus won't feel punished.

Regarding style, I think the concept of walking above the ground to be much neater. Plenty of things glide and float. Not many walk above the normal horizontal plane. ^_~

I had a Shadowrun mage once that used a combination of levitate and another spell (I forget which) to travel horizontally at great speed. She'd levitate a foot or two off the ground, then use the other spell to propel her forward. For stylistic effect, I used her staff as a guage-- holding it vertical meant she stayed still. The further she angled it towards horizontal, the faster she went. It was rather fun watching this mage come speeding up to someone, and yank on her staff like a car emergency brake to come to a stop.

There are all sorts of similar things that could be done. Wear feathers, for instance, or act like riding a broomstick or hobby horse, or maybe seat oneself on the 'ground' and glide along like on an invisible flying carpet. =)

As it makes no mention of giving you a bonus to Move Silently then it does not give a bonus. As a GM I would allow you to negate the circumstance penalties if any for any objects or items on the floor which would cause a noise.

With regards the jumping, I would say that you can only do that if you are within 1 foot of the ground. Levitating any higher and you are not able to jump. If you can't run then you can't jump.

Style-wise, this will vary from person to person and game to game. I personally would have a very lazy mage who couldn't be bothered to walk, he remained stationary while the world moved to his command.