Seems to me that computers do generally perform their tasks reliably. (I say generally, not infallibly; cosmic rays and power failures and such). The issue is really about whether their human programmers have successfully programmed the computer to do the intended task, and about whether their human operators are successfully interpreting computer outputs. So this is surely about what constitutes an expert witness, and how reasonable it is to rely on the testimony of an expert witness, where computers are concerned.
On can really consider how rare hardware issues leading to wrong computing are for your widely used computer chips. In general it seems they are very reliably correct and fixed in reasonably quick order.
Same really cannot be said about software. But on computational level it is actually amazing when you think about it.
