If he can't already cast the spell, there's a chance he'll make a mistake.
Then the Scrolls section states 3 conditions to use scrolls;
To have any chance of activating a scroll spell, the scroll user must meet the following requirements.
- The spell must be of the correct type (arcane or divine). Arcane spellcasters (wizards, sorcerers, and bards) can only use scrolls containing arcane spells, and divine spellcasters (clerics, druids, paladins, and rangers) can only use scrolls containing divine spells. (The type of scroll a character creates is also determined by his class.)
- The user must have the spell on her class list.
- The user must have the requisite ability score.
Emphasis mine. So does that mean that a sorcerer can use any scroll as long as the scroll's spell comes from the wizard/sorcerer spell list, or will there be a problem when using a scroll of a spell he does not know.
I would assume the same also applies to a bard?