tennis_trs
2010 2.0 Roadster Sport
I can think of lots of reasons why giving your phone to family to play with isn't a good idea (Do you have one-click enabled in Amazon? Will your son delete your appointments or create new ones and invite your business associates?). Accidentally starting a charge on your car seems a lot less worrisome.
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There are plenty of other things they could mess up, but most of them aren't part of a neat app. My main concerns would be setting/charging at too high of a current level or screwing up the OVMS settings. I would only give my phone to people I believe won't purposefully do bad things to/with it (and accept the risk that they'll screw up something by accident).