We've thought about letting people turn it on or off, but have held off for now. We're only sending the edns-option to authoritative DNS providers who also handle the HTTP request, and thus would have seen the entire src_ip anyways.
If you've ever seen the painfully common DNS issues on Verizon Wireless, you'd know why I'm asking. ;)
Authoritative nameservers handling http requests? Mine certainly don't.
Or did you mean to say that you only send edns-option to the server that is authoritative for the domain being requested?