Adeline, Resplendent Cathar's tokens should not be allowed to enter attacking a battle

Adeline's trigger says that when you attack, for each player, put a token into play tapped and attacking that player or a planeswalker they control. It does not allow for attacking battles. I believe this is the only card that puts tokens into play this way - everything else seems to either not specify what those tokens can attack, or only triggers when you are already attacking a player or planeswalker (i.e. Combat Calligrapher).