We can't regulate the spam files any more than we can regulate the files that you share from your computer.
Most LW users learn to differentiate between good files and bad files...after a little trial and error, reading the forums, etc.
The thing is, many people post on the forums stating that they are giving up LW because it's too much of a hassle...files won't download...files aren't good quality...files aren't what they say...as long as people are deterred from using LW, spammers will continue to spam.
It doesn't take very long, however, to learn how to avoid spam. Read the forum threads. Use Limewire's filters. Know what you're looking for, i.e. what size file you should be expecting.
I personally don't think that frustration will cause the spammers to stop. They'll probably keep coming up with new ways to spam, just as we will keep coming up with new ways to avoid it.
Good Luck