@Valeriya24
A guest asking for a discount AND and early check in AND to communicate off platform, is a massive red flag.
However, I think @Helen3 is right. It doesn't matter if previous guests didn't have a problem with it, something like having a curtain instead of a door is significant and should not only be mentioned clearly and prominently in the listing and shown in the photos, but probably mentioned to the guest in a message before they book, to make sure they are aware of it and okay with it. I cannot imagine that this is the last time you will get a guest who is not happy about it.