If you login to a sky router, click advanced>wan setup and read the help text on the right side it says...
Respond To Ping On Internet Port
If you want the Sky Router to respond to a 'Ping' from the Internet, click this check box. This can be used as a diagnostic tool. This can be a security problem. You shouldn't check this box unless you have a specific reason to do so.
My bro who services servers for a living said 'I tend to switch pinging off at the router to stop script kiddies finding a live IP they can port scan, there are no effects from switching this setting off.
Some bad advice is spewing from this thread, there can be no good reason for someone advising this to be enabled.