[throwaway0a5e]

When you encounter things you don't understand in complex engineering it's not unwise to copy them because you are either copying a harmless mistake, irrelevant appendix type feature or it's a key feature you don't yet understand.

[blaser-waffle]

Plus the cost overhead for a few more rivets isn't crazy; even if they're superfluous and you know it, better to spend brainpower on more complex and critical engineering.