Wow, this is amazing. Thanks a lot 
As @zancler said, totally spot on.
I only have one concern with this kind of feature (declining payments under certain conditions). Even if it’s the user the one giving the order for us to not let them spend more there are certain situations in which you actually consume the good before paying, restaurants mainly. In one of those situations (let’s say you don’t have reception or any battery left) the “drunk mode” can be really painful as you need to deal with a bill and a card that doesn’t work. So, yeah, something tricky to balance 