Yes we do use lsclient, the SE's are afraid of what may be involved with Active Scanning and don't want to try it since LSclient works and I got tired of asking for it.
As far as firewall we have all of them turned off. However every so often I look over the RPC error report, kick off lstrigger and the PC's scan just fine. They will show up one day and not the next. Again, this doesn't happen very often so it's not a concern to me. The reason I am asking is that it seems like a simple feature and with InstallFree the programs don't show up until they are downloaded (with the Offline setting) so putting some time between the LS client and the scanning would help us out.