Google has revised its Play Store rules. This is new:
Apps and their ads must not add homescreen shortcuts, browser bookmarks, or icons on the user’s device as a service to third parties or for advertising purposes. Apps and their ads must not display advertisements through system level notifications on the user’s device, unless the notifications derive from an integral feature provided by the installed app. (e.g., an airline app that notifies users of special deals, or a game that notifies users of in-game promotions).
I’ve never encountered any of these, but good to see them banned.