I don’t know you, Ken, so I don’t know what reviews you have. For the sake of making a point, I’m going to imagine that you’re new to the platform and have no reviews at all.
As a sitter, I could presume that you’re a good bloke, and maybe you are, but that assumption might prove to be very wrong - for all any of us know, you could be a predator! How on earth would we know?
With no reviews, I’d weigh things up and would I stay with you before the sit? No way. I’d expect you to understand why and I’d be glad of the THS protection there. That’s not ‘paranoia’, it’s about ensuring a minimum level of protection. More women than men will understand and identify with this point of view because we tend to protect ourselves routinely.
Let’s now assume the opposite scenario; you have loads of great reviews. You’re a verifiably great bloke. Will I stay with you the night before? Sure. No problem! We’ve had a chat and agreed to it - it’s all good.
All of that said, even if you had glowing reviews, I would pull out of a sit, or find other accommodation if you told me “things have changed and I’ll be around a night or two before”.
Presenting sitters with a fait accompli*, when you haven’t checked if that suits them, isn’t okay. We’re not there to hang out with the homeowners and personally, I can’t maintain the necessary confidentiality in my remote work while someone is there in the background.
There’s no need to be offended by a policy - there are some very good reasons that it exists.
*as has been the case for the OP.