A jury is already allowed to make any inference they want.
No, they aren't, which is why jury verdicts (except for criminal acquittals, which are Constitutionally special as a limitation on the ability of the government to impose criminal punishment) can be overturned as a matter of law by the judge (or an appeals court) if they are not supported by non-excluded evidence in the case from which they are legally permitted to fraw the conclusions they have and from which the judge or appeals court finds a reasonable jury could make the inference.
OTOH, juries generally are able to draw negative inferences from destruction of evidence, and even in some situations from failure to preserve it by a party, and more generally from conduct of a witness bearing on their general credibility or their credibility on the specific testimony at issue.
So the jury instructions would be pretty powerful if the judge said, "You should consider the lack of bodycam footage as beneficial to the Defendant. You may reasonably find that the accused's testimony is more credible than the officer's during those 17 minutes."
True, but not the issue here.
> A juror is free to infer that you are guilty when you plead the fifth,
No, they aren't, which is why:
(1) If the trial judge decides before the case goes to the jury that a reasonable jury could not convict the defendant without making such a prohibited inference, the judge can dismiss the case, either in response to a defense motion or on their own, without even sending it to the jury,
(2) If the trial judge makes the same determination after the jury returns a conviction, the judge can toss the verdict and and acquit the defendant (which they could not do with a jury acquittal), and
(3) If an appeals court reaches the same decision after the trial judge has accepted the jury verdict and entered a conviction, the appeals court can reverse the conviction (which they could not do for an acquittal.)
Criminal acquittals are a constitutional special case of jury freedom in the US, as a special protection against imposition of criminal punishment by the government. The freedom juries have to ignore the law and facts and acquit because they feel like it in criminal cases is neither symmetrically reflected in a similar freedom to criminally convict, nor manifest, in either direction, in civil cases.
> "A juror is free to infer that you are guilty when you plead the fifth"
Indeed, but they are _not_ supposed to do so only because you plead the fifth, but presumably because of other evidence. In a civil trial, AFAIK that is not the case, the jury can infer you are guilty because you did not testify in your defense.
There's a lot of places in society where people ought to infer the worst if the data is hidden from them, but people continue hiding data because it works.
To give an example, I remember when FTX put out its "balance sheet", which was basically a one page spread sheet with visibly-obviously BS round numbers in it in some places. It barely qualified as a joke for a multi-billion dollar enterprise. But there was still some people... a minority, sure, but not just one or two people... arguing that, hey, maybe it was still all on the up and up and if we could just see the real info it would all be OK.
But we were entitled to conclude from such a balance sheet that FTX was a scam enterprise. It would be theoretically possible that we'd be wrong in such a conclusion; being entitled to conclude something is not the same as being guaranteed to be correct about the conclusion. However, in this case, the many who did conclude from the hiding of the data that the hidden data was about as bad as could be were have been correct.
Many people conflate being entitled to conclude something with being guaranteed to be correct. It's worth pondering the distinction if you don't immediately get what I'm saying. It is related to the question of "burden of proof"; in this example, for good and sufficient historical reasons we are entitled to assume that a company is being naughty (not just in the crypto space, in general) and they have a positive burden to prove that they are on the up-and-up. Failing to do so is not proof that they are behaving poorly. But it does mean we are entitled to assume and act as if they are behaving poorly, and it is their responsibility to prove otherwise, not ours.
That's how things should work, but wouldn't the idea in question mean that, just as with other zero-tolerance rules, common sense like that wouldn't be allowed anymore?