You'll see it when you've signed up to f8lure.
Lol, I've been in that page many a time and never spotted that before.
Go on, hang a spare router off the HH3 and put it in the DMZ 
What a backwards way I doing it... Seems a bit of a waste of electric to stick a router on the end of it just to respond to pings and no other reason. I wonder why BT don't have it on their routers? Perhaps they don't want people being able to monitor latency
I've also heard that it can cause a slow down in responses for general web browsing, as it tries to access the DMZ first before checking anything else on the network?
Is this the case?
Does something have to be on DMZ to respond to a ping, or is there a port that could be forwarded to a device to respond?