Last year Bleu nord was marked out in pitches when I arrived 5am on wednesday morning.
Controllers were being very strict, even at this time of the morning, where you could camp, with threats to remove camping passes if you did not conform to requirements, ie next available space with no gaps to the previous arrival. You could not pick your spot in the field.
I had my ACO invoice with me to prove that I had 4 passes, and had a big arguement before they let me stake out x 4 space, had to threaten to get the ACO office involved.
I would suggest to be safe that the first arrival takes all the camping passes, so that you can prove you have paid for the space, even if this produces some hassles when later arrivals turn up.
I don't know how the scanning will work, but I would avoid them scanning tickets (if that's what they are doing) except for the one you are entering the site with.
Look forward to the early reports as to what's actually happening.