@TracieandJason0
They dont see the reason why - unless you tell them via a message why..... just decline and choose the most appropriate reason for doing so.
Only once have we replied to a guest and told them why we were unhappy hosting them: the requested to book, and when we said yes, they came back and started haggling. We said, sorry, you should really look for something in your budget - there are many other properties in the area that will suit.
He then came back and apologised saying he thought it was ok to haggle - I said no.
Cutting a long story short, he stayed with someone we know and he got a glowing review. So...