Just because the files don't show up in a search doesn't mean that they aren't shared. I am behind a NAT firewalled router connecting through UPnP. A wild guess would make me dare to say that I share the same kind of files. I have tried asking friends of mine search for files that only I have and nothing comes up but spam, which means that I am not browsable. But people upload from me from maybe 10-15 minutes after I connect to the network all the same. But can't start the download unless they find a searchresult.

I notice though that the same IP will maybe try for 2-3 uploads that I have almost at the same time, and suspect that some hosts that I download from can browse me.

I do not have access to my router, so there is no way I can fix this. There might be several others using Limewire under the same circomstances.

As for getting rid of freeloaders, I can only say try setting the limit higher, to maybe 30 or 50. I seems to help allthough the filter doesn't work every time. I have it set on 30 and I sometimes browse people uploading from me that only have 10-20 files, which would be ok if it was the right kind, but it isn't.

Use the keyword filter to get rid of spam, and the junkfilter if you are using a newer version. Organize by filesize instead of number of hosts. And use bitzi

Don't block IP's because a lot of people use dynamic IP addresses, so you will only be blocking legit users the next day. Only block IP's that you are sure are static. The only way to find out which are static is by writing down IP's and comparing, but Im to lazy to do that