Whether it is something I would get into or not is irrelevant.
This is your polyship, not mine. But you haven't "gotten into it" yet. You are kinda checking out the offer here, right? So... check it out thoroughly then.
It sounds like you have a plan -- meet the woman and ask what this is all about. So... meet her and ask?
And don't just ask why
this is in place, could ask if this is a hard limit (will never change) or a soft limit (could change over time or change after X encounters). Maybe that makes a difference to you. Maybe there's some trauma story of her own there.
But if in the end you get some kind of answer and it still bugs ya? Step away and say "Thank you for your time. But this is not an offer I want to participate in." And walk away. The price of admission here is not to your liking.
Not every date is gonna be a long haul runner. *shrug* That is what dating is for -- to find the compatible ones.