I think this question is weird, but everyone here probably won't

. The only reason I'm asking is because I couldn't find anything on it.
So, recently a few of my sisters and I were discussing when we went through formal recruitment as PNMs (some older actives, some newer actives). We started talking about one sorority in particular because during their party, they would take pictures of the PNMs (round 1 only). They would bust out a fancy camera and say it's for their scrapbook, which was obviously a lie. My school is a fairly large commuter school and we do not have a terribly large Greek system. We also don't normally get recommendation letters/pictures of PNMs for recruitment.
So, my question is, is taking pictures of PNMs during recruitment a normal thing? Or is it even allowed?
If it's not allowed, I seriously wonder why they have not gotten in trouble yet. This has happened at least 3 years in a row. Thanks for any and all responses!