One of my players would like to cast magician spells on the sly, and I’d really like to let him (it’s one of the rules I always loved in L5R). Caught by bandits? Under dagger-point up while they are deciding what to do with you? Casting Thread of Friendship on the bandit leader without his cronies catching on seems like (1) a fun idea that could move a story forward with either success or failure and (2) something that should increase the difficulty of the test.
My gut says to simply make the required test harder than is required given factors, target’s will, etc. It’s simply quite a bit harder to get the necessary chants and gestures right when you are disguising or hiding them. Here’s the idea:
Proximity: Far, close, immediate
Individuals to hide from: One, more than one
Attention (use attention of a representative member or members of the group or groups to hide casting from): Directed away from the group, directed at the group, directed at the caster
Success means that the spell is cast without observation, and, if the consequences of being observed casting are dire, then being observed (successfully) casting by one or more individuals would be a good twist.
What think you? Muse. Poke holes. Bring concerns. Criticize constructively.
Allow a Scout test to cast the spell when their attention is distracted, twist: they notice and interrupt the spell, possibly quite unhappily.
The casting can be covered by some kind of performance that incorporates the chants and gestures, allow a Manipulate, Orator, or Singing test, same twist as above.
Magicians are plenty powerful and don’t need special concessions to sidestep one of the few limitations of their class.
There’s no “putting a sword in your face on the sly” or “having an argument with you on the sly” so I don’t think there should be casting on the sly.
FYI, my goal is make discreet casting difficult. I might even start the factor list I suggested early at 2, just to be safe. I want this to be something the magician really has to work for – you just have to use your traits and wises, throw in some persona points, go all out, risk the twist. It’s a BAD day for the magician if he has to cast discreetly. It shouldn’t be easy. That’s my goal, at least.