I think you need to re-read the suggestions. The only things I suggested NOT allowing teammates to break down are ammo boxes, and a limit on the sandbags they can break down.
There is no situation is which teammates have good reason to break down a friendly ammo box.
In the case of sandbags, I get that there are cases of trolls, but all too often there are instances of players going up and breaking down sandbags on windows because they want their AI to be able to shoot out and get free kills for them.
In these instances, there needs to be a limit on how much they can break, otherwise they end up getting a handful of extra kills, but cost the team a LOT of deaths.
There needs to be a way that this can be detected that is fair for both instances, dealing with troll structures, and sabotaging structures just for a couple extra points.