As my arguments have grown more refined, I've noted a particular argument of last resort among my opposition. After they've been forced to admit that it is a fundamental injustice that rational, competent human beings are routinely denied the right to decide what they do with their own bodies, rather than just accept that the situation needs to change, their final argument is that we must "err on the side of caution."
What this argument represents, is the false assumption that we simply cannot know for certain who is and is not competent to make their own decisions, and therefore we must restrict the rights of people we are actually fairly sure are competent in the hopes of getting all the ones who aren't "protected."
There are two fundamental errors with this argument. The first, and most obvious, is that there is no inherent need to "err" at all. It is perfectly possible to examine an individual's mental capabilities and knowledge base to determine if this individual is or is not up to the standard for informed consent. Talking about which way you would rather err means nothing when the goal is to simply not err in the first place.
Because, we should be clear, the individuals who bring up erring on the side of caution aren't talking about making the examinations potentially more rigorous than they would need to be. They're talking only about maintaining the failed system of age lines that, by this point in the argument, even they have been forced to admit are not capable of accurately sorting those who can provide meaningful consent from those who cannot.
The second error with this argument is that it assumes as a given that in the eternal debate of freedom versus security, the right and proper side to err on is security. That has been, by no means, established in any particular issue you care to mention, so there's no possible way for it to have been established in the general case as such individuals argue.
The entire point of a legal system founded on "better to let ten guilty men go free than that one innocent man be punished" is to err on the side of freedom. Everyone who's ever been offended by seatbelt laws, helmet laws, or speed limits understands that the tradeoff on freedom versus security is never cut and dried in favor of security.
I'll admit I am an extremist. Anyone reading this blog who is surprised by that has probably not been paying attention. I fully support the right to hate speech, even against me. I'm of the opinion that the right to bear arms means the right of the private citizen to bear any weapon that the government sees fit to place in the hands of its military, and that includes nuclear, biological, and chemical weapons so long as the government in question asserts its own right to those weapons. I may make another post in the future discussing this point in more detail, but suffice it to say that on the freedom versus security debate, I'm going to choose to err on the side of freedom every time.
The worst of it, though, is that choosing to err "on the side of caution" (including times when it isn't necessary to err at all) isn't a consequence free choice. There are real harms inflicted on people when they're denied their rights to bodily autonomy including sexual autonomy. You could try to argue that those harms are lesser than the harms inflicted on someone who has been improperly deemed capable of informed consent and thus "fair game," but you cannot deny that the harms in the former situation simply do not exist.
I've frequently suggested, in response to the idea that we should "err on the side of caution," that the correct course of action would then be to raise the age of consent to 40, 60, or maybe 80. For some reason, no one seems to think it's a good idea to "err on the side of caution" in those situations.