How the list replaces the scroll
The trick is that replies never pass through a chat. Your invitation goes out on WhatsApp as a single link, and the answer is given on the page that link opens. From there it goes straight onto one guest list, no matter whose group, whose private thread, or whose forwarded copy carried the message.
One link means one list. If Anna forwards the invitation to her partner's family chat, their answers join the same rows rather than starting a parallel headcount you have to reconcile later. Nothing reads your message history and no bot sits in your groups; the chat stays exactly as private and noisy as it was, because the tracking happens on your page instead.