If the offer to share is turned down, then taking it away can appear to be a great way to teach them to be nicer next time. No orange, no more problem.

As a solution it will usually lead to an interesting mix of responses. Anger, frustration, tears or disinterest. But it causes two relationships to be damaged.

Impact
Not only will each child hold a grudge against the other, but they are likely to hold a grudge against you too!
It was only an orange. They were just being kids. They may choose not to come to you next time, if it means losing something.