Hi,
- We are in the rental business since 1993 and we've seen the same scenario 100's of times.
There are many clients that know well (and some of them very well....) how to take advantage of the hosts (landlords).
So to quickly resolve this matter let me explain you how you can handle special deals.
- When the guest arrives remind him that you gave him a deal pending that he stays the whole lenght of time booked, but also let him know that he doesn't have an obligation to stay the whole lengh of time booked, and remind him that there is no law anywhere stating that he has to stay, it is stricktly up to him and nothing to do with you. As far as you are concerned he booked and paid for the time requested, he wants to leave earlier... well, feel free to go. You have no obligation to refund anything and next time do not engage in any discussion related to it, period.