The scoreboard start tile is a custom variant, wide open to house rules. I’m certain that everyone who will use this variant will agree that dragons, towers, etc. cannot remove scoring meeples from the board!
Again, the primary purpose for the scoreboard start tile is so that the players sitting next to the scoreboard in a game with more than 2 players do not have an advantage when playing with The Messenger or The Robber mini expansions. I want all players to have a better view of the scoreboard, not a way to attack it!
Another way to avoid all of this is to design your own start tile with pure field tiles in all 16 surrounding tile spaces. I designed the variant so that everyone can design their own custom scoreboard start tile!