I choose to not call a GP a liar or too thick for being unable to differentiate between apps :)

I also chose their presumed first hand statement than your unrelated experience with unrelated third parties.

Your point re: having to subscribe to WhatsApp notifications, if we're staying in the realm of "what ifs" and looking for the awkward but possible ways to discredit the claims, I can believe that she was enrolled without being asked. I've seen at least one person complaining about that exact scenario.

Cheers!