Well ... I've noticed that for me the "Browse host" option is always greyed out for fakers and I've hardly ever seen that for normal users. I'm not talking about being able to browse but getting a zero file return.
So what causes the greying out of the Browse Host feature for some hosts? Is it network latency, or is it something in their client that disables browsing? If the latter then I would still suggest that such hosts are not normal users, and are certainly not running LW/FW or Cabos. An option to filter search results (and to prevent downloads from and uploads to) such hosts can only protect the network and help reduce the overpeer problem imho.
Anyway, if its an unreliable method then that's ok, not the first or last time I've been wrong about something. Just thought it was worthwhile asking