You cannot go to someones town and get their camper to move to your town. Impossible. You can only get their moving villagers to do so. Please stop confusing people with thiss. It has been proven impossible ok guys.
If this seriously needs a second opinion even though Lyla already explained it perfectly:
You CANNOT, under no circumstances, convince someone else's camper to move directly into your town! No more confusion. It's been proven it does not work multiple times.