Well for me its a part of the templates. For example I have a template that promotes big cocks + a redhead sponsor. As I mostly do in big tits some of the recips on the template (both for link lists and TGP) have recips on them that are to big tits link sites or big tits TGPs. Once in a while I use the template with pics of a redhead with small tits getting a big cock. Obviously I can't submit that site to Big D Titworld... or Boobfind. But the template still has their recips on them... simply too much trouble removing or replacing them.
It could also be "trick" to get listed with you
I remember shortly after I opened up my TGP I got some pretty good galleries submitted. It sort of tipped me of that my recip was placed between Thumbzilla and Tommys. A new TGP open for less than a week... shees
I found some other galleries from the same submitter... only recip replaced was the one between Thumbzilla and Tommys.