iPhone vibrating for no reason

[Chakravartin]

M A V I C wrote:
I did that once. Are you running iOS 6.0.1?

Yes. On both devices. And we had the 4S playing music through the radio through much of the weekend. It came away with a 100% charge.

Do you have the phone in a case? If so, try docking it without the case.

Maybe a backup-and-restore with iTunes would help.

If those things don't work, I'd contact Philips and ask them if this is covered under warranty... Because the next thing that I'd suspect is a defective clock-radio.