Would would hope that a big service like Twitter has checks and balances in place so no "lower level dev" can add whatever they feel like to the production service.
Lower level can equally mean 'direct access' or 'service level' it doesn't have to be a corporate hierarchy thing
Every dev has low level access at some point be it writing or approving production code where do you think the concept of Easter eggs comes from which these clearly fit the description
It seems however we've gone so far up the ass of the corporate machine that we have become synonymous with it
I read a funny excerpt the other day in a book -- when Rome was full of slaves everyone started adopting a slave mindset because it was everywhere pretty soon you can't distinguish slave from master and so it is here when we as devs put ourselves into comfortable stereotypes but what do I know I'm just a low level dev