I have broadly re-interpreted the rule as: any sorcerer can study any sorcerous script (magician, cleric or any of the sorcerous subclasses) and attempt to learn its secrets, with some attendant risk. The chance to learn is based on the Magician/Cleric Chance to Learn New Spell (d% vs. Int or Wis, as per Tables 4 & 5), the risk of some misfortune striking is a Non-Standard Task resolution (throw of x-in-6, as per p.137) and then avoiding the misfortune triggers a Sorcery Saving Throw.
This is part of my general "Yes, but..." attitude when it comes to rules: you can try just about anything, but there's usually risk.