If we assume a stable system, not connected to any network, and fully backed up, what damage can cutting the power do?
Obviously it's a hassle to restore an image of the card, but a fairly minor hassle. Could the card be bricked (buying a new card is a minor expense but a more significant hassle)? Could the Pi itself be damaged?
I'm going to be building a Pi+touchscreen into a piece of equipment, which will have a swicth that can cut all power, and I don't trust my users (starting with myself).
Over the past few years we've been pulling plugs out of hundreds of Pi's, every day sometimes multiple times a day. We did have 1 or 2 Pi's blowing up, but I sincerely doubt it had anything to do with pulling the plug.
So I wouldn't worry to do the same. Indeed, the worst that can happen is that you'll damage an SD card, which can be recovered easily by reformatting it.
But IMHO you'll need to be extremely unlucky to even get into that latter trouble.
EDIT: rough calculation: at least 100,000 plug pulls (or the equivalent by power cuts or switching off the mains).
I agree with EDP, no damage should come of pulling the plug, but if you have sensitive data on the sd card, don't pull the plug(unless the OS is frozen, and nothing is happening, and nothing will happen). I only had to pull my plug twice, both times because of XBMC. Rasp bias hasn't given me any problem, nor arch Linux or Ubuntu.
