Law For Alts Under 60

[Noxifer]

I have an alt too and I don't not play that alt as often as my main character.

That's not what this is about. When they talk about "alt classes" they are talking about classes on their main character, just not their main class. So if you've picked up Arcanist and Thaumaturge, and levelled Arcanist to 60, you don't get the law tomes if you do the low level roulette (or trial or high) with your Black Mage until that class is 60 as well.