I think it would be a good idea to implement a way to prevent other players in the player's party from smashing the inside of their ship up. I mean, if you're in a party they're probably friends, but even friends grief each other. Maybe make it togglable, so that if you want your friend to help smash things they can, but you can stop them from doing it if you don't want them to.
I agree with this. It would also help when you're just redecorating on your own. For example, I decided to re-panel my ship with soft brick the other day, but that involved knocking out the copious numbers of decorations I already had set up--including some storage units, which was a double hassle. If I could have locked those decorations, I could fiddle around with my background to my heart's content.
At least make it take more than two taps with a pickaxe. Also What is the point of locking a door if someone can just tap it with a stone pick and take it away?