That's not to say no records will ever be held by transwomen - because to me, why shouldn't they be? But what those records will be is not unbeatable, because you'd have to get it quite spectacularly wrong in the face of everything you know of a transitioning athletes performance for that to be the case.
But @RatRolyPoly you've literally just said, in response to me, that 'everything you know of a transitioning athlete's performance' could be the square root of bugger all!
So you pretty much always have to go on the best evidence you can gather at the time, and be prepared to roll with advances later down the road.
Unless you're suggesting that you look at every single person who wants to complete at elite level as a woman, their performance history and competition positions and say 'this person is clearly still too much like a man [i.e. too good at their sport] to be considered a woman and they can't compete' - and who on earth will be qualified to make that decision, or feel comfortable doing so?
Not to mention the messages that sends about women's sport compared to men's, and the fact that someone could slip through the net and set an unbreakable record because we didn't know that the factor giving them an advantage is, in fact, giving them an advantage. NOT TO MENTION the problem of trying to do this at non-elite levels within the training pipeline.
Obviously, I agree that there will never be enough evidence to comprehensively 'prove' that something is fair, and I understand the need to continually review and revise policies in the face of evaluation (this is what I do for a living). I just think the line is drawn in the wrong place. In sport, why have we decided that testosterone is the be-all and end-all? And what commitment is being made to evaluate the impact of the changes in practice, reported anecdotally on this thread and in governing policies - especially at non-elite levels - on natal women and girls' participation and progression?
Again, square root of bugger all, as far as I can tell. In sport, and in everything else.