It feels a recent addition to me too.
If you're getting zero banners in TW again and again, you're simply not contributing. Your GP is added to the match and by not doing anything you're actually helping the other team. Why should you get rewards for that?
If defences are being filled up extremely quickly, maybe the defences could be tougher? Or (and this is a lot of work for the officers, particular zones need particular teams that are associated with particular players). 'Khelor has a good defensive GAS team that needs to be in south row 2 etc etc'
The bottom line is, I'm happy with the (recent/not recent) change. Reward leeching sucks.