I don't think you can disable this through Claw's UCI. It's part of Cowon's firmware. Claw do include a utility to reset the favorites. Go to Claw's User Settings, select Music and down at the bottom are special options. One is to reset the favorites. It's handy when you want to create a playlist from scratch.
If you need to save your favorites list you can use the playlist function to back it up. This won't stop you from hitting the wrong button, but, you can always reload your backed up list into your current favorites if it ever happens again.