In-laws coming to visit; not coordinating with us?

Simply stated; Write them a certified letter with return receipt telling them that you had to0ld them they had to give you a month's notice,m that they cannot come and stay from the date they indicated, and please not to show up because you will not be able to accommodate them. Plain and simple. If they show up, don;t let them in, plain and simple. If they hold it aginst you, it is them who know no boundaries. You can say in the ltter, it would have been nice to see them, but since you have they type of life you do, it must be arranged a mointh earlier. and agreed uponh.