I have read on more than a few occasions that the Maple Leafs have not had an unsold seat since WW II.
Everything else I read today does not mention the Leafs with the longest streak.
A few of the guys here at my Golf Club are are from Toronto and are always bragging about no unsold seats since WW Ii so I don't know who to believe. I think fans of the Montreal Canadiens might take issue with the BoSox streak. I go back to the late 50s following the Hawks and the NHL and check attendance figures daily and if the Maple Leafs and Canadiens did not sell out a game in that time it would be like earth shattering news.