I would post in the BitcoinSpinner forum/thread, but I'm a noob so I can only post here. I just got started using Bitcoin last week and have been making very small transactions (I have less then .02 BTC still) until I can manage to get verified on Dwolla and MtGox. I have wallets set up on my Nexus 7 (with BitcoinSpinner) and on my PC desktop with bitcoin v0.7.1 (full block chain history downloaded finally). Meanwhile I have imported the private key of my BitcoinSpinner app onto my PC and into MtGox, which was apparently a mistake because it appears that any BTC that goes into a private key that has been imported into MtGox they seem to freely transfer to accounts owned by MtGox that I can't fully control. So now any bitcoin transfers that go to my BitcoinSpinner address automatically leave the "device" and go into MtGox (still in my MtGox wallet at least, thank goodness, but not under a private key I know). I'd like to be able to generate a new private key for my device, but I don't see a way to do it. Do I have to un-install and re-install in order to do that (would that work)? BitcoinSpinner is kind of useless if any funds I put into it will get automatically mysteriously transferred out at an unknown time, leaving my Nexus 7 with access to 0 BTC.
BitcoinSpinner uses a type 2 deterministic wallet.
You should never import a private key from a type 2 deterministic wallet into a third party service, such as mtgox.
I think the BitcoinSpinner app should warn users against that.