Hi @jones.eth and @Sanne !
The reminder e-mail is only sent if guests did not follow the instructions of the previous email and did not complete their online check in.
Just like (for those hotels that have the package) the SMS reminder for online check in is only sent to guests who, until that point, did not finish their online check in - therefore only messaging guests to whom that message is relevant.
With that said, I agree that this email should be optional for the hotel to decide to send or not. Thanks for upvoting the idea - we keep an eye on those and try to see when is the right opportunity to address that improvement. đ
Cheers!