I don't think that this is a good idea for many reasons

1. This would make Limewire use much more CPU. Picture yourself downloading lots and lots of musicfiles with a fast connection. Every time a song is finished first it's needs to be verified which allready use a lot off CPU, then it starts your Antivirus which also will use a lot of CPU. This would make Limewire have a lot higher systemrequirements

2. You can have a saved folder for saving, then scan the folder all files in it at the same time. Then you can move your files to another folder and share that one instead of your saved folder.

3. You can use Bitziweb to see if files are legit. Look at filesize etc. And not just click on any file that matches the name. Look at the threads in the "Tips and Tricks" part of the Limewire forums, and also have a look at this tread:

http://www.gnutellaforums.com/showthread.php?t=41432

4. Just learn to be more careful when using P2P