i know several yards that ask for the passport. The passport does actually belong with the horse, its not proof of ownership etc. If your horse was injured when you wernt there then in theory it couldnt be treated by a vet until you turned up with the passport.
Saying that - The only time i have handed over my horses passport was when being professionally transported up to scotland to go on loan. I did take photo copies of every page to show i hadnt filled out the change of ownership section etc.
None where I am now- we have a set closing time for the yard (9pm) with exceptions for horses who are ill and need monitoring overnight, etc.
I used to ride a friends horse up at an awful yard. They actually had a rule that some form of whip had to be carried at all times while you were riding! You had to sit back and watch beautiful, talented horses being turned into nervous wrecks because of the way they were treated. If you said anything you were chucked out the same day and banned from the yard.
I fell out with them and haven't been back since.
This is why i opted to rent my own field & stables!! I have been on yards where you cant enter the yard before 8am or after 6pm unless in extreme emergency.. not helpful when you work normal office hours. I was asked to give a copy of my passport which i didnt mind as i still had the original. Some rules make sense but some just seem to be there for the sake of it and are not practical!