Be careful about what folders you share!!! You can decide which files & folders to share. Just select them in the LW Library window & right-click & to decide whether to share or not this file or folder.

As previously mentioned, he should be careful how he goes about sharing his files. Normally the default location for downlding is C:\Documents and Settings\"your account name"\Shared
The newer versions of LW also allow you to immediately share your downlds as soon as you downld them. This is an option you can turn off. However, I believe the biggest issue here is what folders he is sharing. Nobody should be able to find his username via LW. Not unless he is recklessly sharing everything. Unlike some other p2p programs, the directory path makes no difference, people can't see what the directory path is. So there's no reason his username should show. Not unless this neighbour perhaps has a spy program. If yes, then LW is not the issue & I can't see why it should be "unless" he is recklessly & carelessly sharing folders he wasn't aware he was sharing.

I believe in the future, LW will be looking at folders or files you can share to "friends" & not necessarily everyone.