Yes. Ulys shows you each proposed trade before it runs, with the asset, the amount and the fee. You can change it, approve it or cancel it. Nothing moves until you approve it.
Smart orders work a little differently. You approve the exact terms when you create the order, and Ulys executes it only on those terms once your condition is met. You aren't asked again at the moment it runs, so read the terms before you confirm. You can cancel a smart order any time before it executes. See What Is a Smart Order?.
Ulys can't move your funds without your approval.