It was well known in the kpop community that the members were not allowed to date, usually it was written explicitly in their contracts. It messes with the certain image they were trying to portray, and affected their popularity. You can't get millions of girls world wide to fall in love with you, and spend their money on you, if they knew you had a girlfriend. It shatters the allusion. But... men being still men, mangers and agents soon found out that these boys would still find a way to get what they wanted. This was tricky for the members though, they had to walk a find line on having a relationship and keeping it secret, and that was usually harder than not. Still, some had girlfriends, usually girls in idol groups who had similar contracts and similar constraints. That still... wasn't the safest option. You knew that fans... could be for lack of a better term... intense. They would spend hours upon hours, dissecting photos, locations, videos, anything that had these idols in it, to possibly put the pieces together, about who was dating who, and who was in love with who. So... thats where you, and the 7 other girls stepped in. You would get hired, by your agency, to be "girlfriends" for the night.