Hi Lisa, you are so right. I, accidentally, significantly discounted a guest whilst getting to grips with the AirBnB system and bingo I was marked down for value and got a private comment that 'he noticed my prices had gone up'! Thankfully that was the last we saw of him.
Had another close shave recently, when I discounted a winter month; what I assumed I was doing was inserting a daily rate when in actuality I was entering a monthly rate! Thankfully the guest sent me a message to confirm the $200 rate for the month, as she thought it was very good value! Managed to correct that before disaster struck.
Love the idea of accepting the booking at the original value and not mentioning a discount.