That's an interesting article, SD, but there's no facility that I can find in my Draytek to turn on ping response. According to Shields Up! it doesn't answer pings, and according to its own control panel, it also sees "Ping of Death" attacks and responds correctly to those. I think I'm glad about that.
I could open up ZoneAlarm on the PCs on the network to pings, but since they're behind the NAT firewall that would only mean they can ping each other, and that's turned on already.
So I remain a stealth-Keef, willy-nilly.