I believe its more about optimization for price and minimum amount of km you need to design something for.
And in regards of screws: If you have too many laypeople doing stupid shit for critical components, you might also think 'lets fix that by adding a barrier'.
Why would that be your problem? Make it a warranty violation, and they can either get it fixed themselves, or pay you money you wouldn't have gotten otherwise.
And in regards of screws: If you have too many laypeople doing stupid shit for critical components, you might also think 'lets fix that by adding a barrier'.