The orange warning banner with the limewire symbol was added because there were bogus LW updates showing up in search results. These files were infected & to try to prevent people from downloading dangerous files, the warning banner was added to LW's interface.

So, if something shows up in your search results like 'urgent LW update - download now' & it doesn't have the lime symbol beside it, you know it's a nasty The LW symbol doesn't apply to music, movies etc...just to LW updates.

If you're getting the massage that LW can't find a license for the file & asks you if you want to download anyway - check this thread for more info: License Warning Option. It's up to you to decide whether you want to download files without a license or not... depends a bit on your local laws regarding copyright infringement.