Blizzard is introducing changes to its parental controls to help prevent guardians receiving unexpected bills.
Starting on January 7, in-game purchases will be disabled by default for all Battle.net accounts with Parental Controls active.
The change affects World of Warcraft, which belatedly introduced an in-game store last month; free-to-play card battler Hearthstone: Heroes of Warcraft; and Diablo 3, although the real money auction house will be closed in March.
To enable in-game purchases, account holders will need to log into Battle.net and retrieve parental controls via email.
Full instructions are available on the Battle.net forums. Blizzard will also be emailing both child and parent addressees associated with affected accounts, but as it is frequently the subject of spoofs and phishing, encourages users to manually log into Account Management.