Darklone said:
How would you handle it? I am evil and ruled that the spell slot is occupied till the spells are used...
Well, as you highlighted, it's only when the spell is
cast that the slot is unavailable. Creating a scroll does not involve
casting a spell, only losing a prepared spell.
However... if I have three 4th level slots and a scroll of Imbue with Spell Ability, then in a way, I can cast four 4th level spells. But once I read the scroll, "the number of 4th level spells I can cast decreases". Now, technically, the number of active Imbue with Spell Ability spells is still less than the numbe of 4th level spells I can cast, so I could be, by one reading of the spell, still okay.
But if I use several such scrolls - or if I cast a couple of 4th level spells - so that the number of Imbue spells becomes larger than the number of 4th level spells I can cast, then the Imbues start being dispelled.
Given that... it seems to me to make sense that casting Imbue from a scroll would require a sacrifice of a prepared 4th level slot. If you've used all your 4th level spells for the day, you can read the scroll... but the Imbue would immediately be dispelled, since the number of active Imbues (one) is greater than the number of 4th level spells you can cast (none left).
-Hyp.