Dear Leigh23:
I hear what you're unhappy about: You want to feel more in control, without penalty.
However, as Airbnb has emphasized, guests make a booking after a fair amount of work on their end, and it is discouraging, even a bit ego-bashing, for them to be refused. I have refused guests because 2 people want to book a room that is only advertised for one, and there are fire safety issues I have to comply with, so as much as someone wants to save money and pile 2 people into a twin bed, my reason for refusing their request (and it always comes as an inquiry, because they are asking for something that my site does not allow), is reasonable and sound.
I've refused guests who have elderly people who want to use my attic--again for safety and fire issues.
Unless you have a valid reason for refusing someone, something you can politely and easily articulate, then perhaps you have reasons that aren't sound, or perhaps you're feeling overwhelmed.
If you're feeling overwhelmed, what I do is block days off and snooze my account: I could easily work 7 days a week for 5 months straight, but that isn't healthy.
Cheers, and best, Elizabeth (7 year host)