The possibly of that scenario happening is impossible..'and piggy's fly' you know
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As we know, no water whatsoever should be used around any computer related connection.- It can short out the computer and the result is the same as dropping an iPhone in the water. Either it works or doesn't...
To get a local factual reply to your question go in person to an automotive electrical shop...I'm sure that he would put it in print for you- Unfortunately i would think that a back yard detailer would not have any insurance coverage.
I would think that the best you could do at the moment is to get her to pick up the tab for the deductible on the cars insurance-....If no insurance sue her. You will win and she will have to pick the complete court charges...Once you get your written 'proof' from the auto electrician ask her what route she wants to take.
May the force be with you