One might want to wipe their drive even if they hadn't copied code, for any number of nefarious and non nefarious reasons.
And they shouldn't. A good way to think about the task of a jury is to ask: if I take 100 situations where these facts are present, what conclusion is correct in the plurality of cases? They are not there to speculate about alternative explanations, they are there to pick the explanation that is more likely than the others.
Isn't the standard in the US that one must "prove beyond a reasonable doubt", which seems like a higher standard than "more likely than not"?
However, many (especially people within the industry, so most of HN) disagree, as does the US legal code.