Excuse me there are crumbs in my mingle.

Mingling in the Market amongst craft.
The word mingle is used to counteract the partial and semi nature of the event.
Mingle is intended I think to imply warmth and welcome. 
The  use of the word semi and partial imply that it's not really open and could infact close at any moment. 
The fact that the mingling is offered for free is a subversive attempt at generosity. 

In summing up ;
Mingling never has and probably never will, come at a cost. So the free mingling in PAM lane is without question under question.