Well, you have to have paperwork claiming it was installed correctly. You don't _have_ to install it correctly. See e.g. doors installed so correctly that they blow out in flight etc.
Sounds like you're upset at Boeing and figured you would tell us you're upset on an unrelated thread. Note that it doesn't really matter if you are right to be upset at Boeing or not. It's still unrelated.
At some point the cost of trying to lie and cut corners becomes worse than the cost of compliance and the airlines and airplane companies will just become good at doing a good job here.