@Kate1995 If the guest has bad reviews, yes, decline. If a guest asks you to accommodate things you don't, like to bring a dog to a no pets listing, exceed your max guest count, etc. just message back explaining that you can't accommodate that and to please withdraw the request so they can find a place that is suitable for them. If you can get them to withdraw it before the 24 hr. deadline runs out, you can avoid declining.
And are you aware of the difference between an Inquiry and a Request? If it's an inquiry, all you have to do is message back, you don't have to either pre-approve or decline.