Lockpicking is no different than herbalism or mining. If you see a Ore/Herb node in a dungeon does everyone roll and then make the person with the skill harvest it and then trade to the person with the highest roll? If the rogue wasnt there you wouldnt even get the chest in the first place. If other people want chest loot nothing is stopping them from leveling BS or Engineering. If I was the rogue I wouldnt roll at all unless there were 2 rogues there.