If this bug has finally been fixed with Late Night and the new patch, may all the Emperors, Kings and Pharaohs be praised! This bug has really bugged me! Would like to share some observations however, for those who, like me, still have or frequently fear the future development of 'run around Sues.'
First, the tag interaction can be initiated from a sim in another room, like in Egypt when the entire family descends to meet visiting adventurers in their homes, so I carefully watch the interaction queue when a child or childish person is in the vicinity. I pause a lot! Cancellation of a tag game, once underway, only works a small percentage of the time. I think I have avoided the bug a couple of times by cancelling only when the other sim is pursuing my sim, then stopping to chat. But if my sim is "It" and chasing the other, cancelling the game will leave my sim in an eternal "chase" mode. Maybe it's just because it's already fixed, but I've only got one die-hard runner now and no kids in the house to work on it with him. Haven't bought LN yet.
Lately, I just let them play until the game reaches a natural conclusion (when the other sim quits). It's tedious, but worth the wait in my book. I've had a couple of runners who actually got cured by playing a complete game of tag!
New to the board, but a Simmer from way back. Pleased to meet you all!