Yeah, that's rather where I was going with that.
Of course, it's not absolute. Your DM may allow every book the players bring him and none of them have a clue. But in my experience most lower-op DMs disallow TOB because it makes the core melees feel inferior (because they usually are.) They haven't yet made the connection that they're already inferior to Wizard/Druid/Cleric/Sorcerer/Bard. (although, this could be because nobody in their campaign knows how to properly play a spellcaster, in which case, the DM is probably right about banning TOB...it's only once people have some idea what they are doing that it becomes apparent TOB is an improvement on melee balance.)