Q about iDisk and deleting files...

I'm just wondering... I have iDisk, and today I tried to delete an image from the Sites folder that I used for a post. But iDisk says I can't delete it because it is in use. So this means if someone is viewing my image somewhere, I can't delete it?

I tried going to the iDisk volume with Terminal and deleting the file, and it deleted fine. Just wondering why iDisk wouldn't let me do it within the Finder?