| Drahliana Moonrunner |
I'd require them to prepare it. Since scroll writing is on your downtime, I don't think that's much of a burden.
Sorcerers and Clerics are not the same kind of spontaneous caster. A sorcerer essentially has all of his arcane knowledge in his head, or blood as if it will. A sorcerer either does not prepare at all.
A cleric on the other hand has the ability to convert his prepared magic.