It's been my experience that the rest of the group is so self-centered -- focused on thier own characters' actions -- that no one even notices when someone hangs back and doesn't "contribute" to a task/battle. As long as the sorcerer has attitude and talks it up at the right moments, it doesn't matter what the heck he's doing.
I dressed up a rogue several years back as a mage, with the intention of robbing the party once they found a particular item. He never cast a spell, and no one noticed -- the goofy personality more than covered for his shortcomings.
I dressed up a rogue several years back as a mage, with the intention of robbing the party once they found a particular item. He never cast a spell, and no one noticed -- the goofy personality more than covered for his shortcomings.