The problem with pinging on a laptop is that the sleep mode never triggers as it "sees" activity all the time.

My MB keeps disconnecting even with the ping running when it wakes up from sleep.

Apple service says that the problem is between the new AirPort cards on the MBs & MBPs and certain non-Apple AP like linksys (not sure if with or without the original firmware)

I'm very upset with this disconnection problem after having to swap the motherboard for unexpected turn-offs :-(

Don't get me wrong, I love the Mac, I've been using one since the Plus, but this problem is really annoying and unexpected.

I use an SMC wireless router and a MacBook Pro, and I *never* have the problem with Airport. Maybe I'm just lucky or something.

I do have the problem on the road when using my GPRS phone, though, which is why the script is useful or me when I go online. I wouldn't expect it to properly sleep while running the script.