So, I my game I add lots of spells beyond what is in the couple of adventure books. Roughly 5,000 spells and counting. When I have an orc ice sorcerer, I want them to have a good selection of ice and cold spells....not just the couple that are in the rulebooks. I like each 'area' to have it's own magic traditions. If find it dull for the evil drown mage seven miles deep in the Underdark casts.....fireball. He instead has Acid Strike. And I do love bizarre spells beyond anything published in most offical books.
So.....enter a small handful of players. They say that they should know all the "rules" before we start playing the game. They note they know all the published spells. So they say if the DM adds spells to the game, they should get the full spell write ups before the game. The players must have all the game rules.
I'm not so sure we count things like spells, magic items, monsters, equipment, and other such things in the game...as "rules"?
I'm quick to point out that a huge part of the players not knowing every single detail of the game is part of the fun. And very begrudgingly this handful of players will accept that....but only to a point. They are fine with one single encounter where I use a spell unknown to them....but they demand to be given the full spell write up as soon as their characters encounter it. I say that defeats the whole point. The players don't know about a spell for a single encounter, then just "remember" and become experts on the spell?
I don't think that seeing one goblin cast Goblin Glue once should take away all the unknown mystery fun of a spell. The handful of players are quick to say that "they the players" just want to know the rules....."the spell". And they agree to act out and pretend their character does not. I'm not a fan of this at all....very few players ever do this....most do the soft exploit of "oh my character does not know what the spell description says, but will just randomly guess the exact right thing...".
My houserules are Spells are Treasure. So if a character finds a copy of a spell written out, and if they can read it, then the player gets a copy of the spell. Though the big way characters learn a spell is a downtime activity. The character needs to be in a small city at least, that has some magical tradition or a library or magic school or a magic guild. Or if the character can find a lone 'private' spellcaster that is willing to share the knowledge. There are downtime activities to do to try and learn a spell.
But in general, a character can't learn a new spell when "on" an Adventure. As my typical adventure takes place in the "Wilderness" far from civilizations. So I player can't just say "oh I walk back to the city to learn the spell". Unless that player wants to remove that character from the game. But, sure, sometimes and adventure will take place near or in a city. But still a character can't fight a couple of vampires, see a new spell...pause the game...and go research it in downtime. It is not like the DM and other players will just sit around and wait.
So....do things like spells count for "knowing all the game rules"?
How does "lore" and "game rules" mix? The lore of a spell can give you a lot of information about the spell....but the "lore" does cross over with the "stats" of the spell. Things like spell range, targets, damage type, effects, duration are al "lore" information, that is also "stats/game rule information". The Stats give you the spell lore for free.
Is it "too much" of a "burden" to force players to use Downtime to learn new spells?