That all sounds very similar to be honest. For Charter and Free magic alike, attempting a spell you aren't familiar with or trying to use Charter marks of power above your skill level can result in serious injury or death if not used correctly...and if any Charter mages other than the Abhorsen try to use Free magic they will be corrupted by it.

[She's broken the Abhorsen rule of not raising the Dead too to be honest...but she'll not mention it yet. If ever. >_>]