Your theory that "contextual evidence" will be enough to ensure fair outcomes is absurd. Either you haven't paid much attention to how this works in the real world or you are willfully ignoring the experiences of people who go through this.
Both from press reports and from what I hear personally, the average outcome of someone reporting sexual misconduct in a work context is a) the accuser is put through the wringer, b) nothing happens to the accused, and c) the accuser eventually has to leave a poisonous environment.
That's what it would take for me to reconsider my belief that relationships within companies are not to be regulated by policies.
My experience is that there is a) no significant difference and b) that sexual predators won't be stopped by a policy (but it makes it easier to remove them).
I actually have difficulties why we have to discuss relationships and sexual misconduct in the same thread.
If you think there should be some sort of law preventing companies from having this sort of rule, I guess that's your prerogative. But you'll have to make an argument why companies shouldn't have the freedom to make what they see as reasonable and necessary decisions about how to run their business.
How do you do that on regular dates? Do you record them? What’s the difference?
Proving is always difficult. You just have to take contextual evidence.
> Or is instead your plan to place a burden on the junior person to report?
Of course the burden of proof is on the accuser. The fact that two people are in a relationship is not a proof. But creepy comments about polyamorism is good evidence.
And yes, the superior is in a weaker position if accused of coercion. So the higher level partner should take a higher risk if the case is brought to court.