Enevhar Aldarion
Hero
You also have to remember that at the time the starter set with this adventure was released, not everything for 5th edition was finalized, that mainly being the DMG. This is why you can find some differences in how some things work in both Lost Mines and Hoard of the Dragon Queen. So maybe who could use a scroll was one of the things changed at the last minute from the starter rules to the printed rules in the DMG. Maybe Use Magic Device was not finalized into being a Rogue-only ability til after the starter set was printed. Or, like someone else already said, the adventure is assumed to be run using the pregen characters, which include a cleric.
