We all know the rules to place a creature into a sanctuary: it will come back after 48 hours. However, it is tedious to collect the return DNA when your creature is leaving the sacntuary, especially if you want to place it back: you have to wait until the spot is released, go to the creatures gallery, collect the return DNA, and then go back to the sanctuary to place the same creature in. Besides being tedious, during the time the spot is open, anybody can place, and even steal the spot for another alliance if they are unluckily around.
Thus, the proposal is getting a pop-up once your creature has left the sanctuary. That way, it works as an alert and also allows you to collect the DNA right away. Then, you could place your creature back in the sanctuary immediately. The pop-up should be displayed in all menus at anytime since you should only press “collect” and that’s it, your DNA is saved.