Tom Sawyer, spot on.
The commercial pressure to get an on time departure these days is shocking. The station managers of some airlines do not give a stuff about 'safety' as they perceive it. They interrupt the crew during their briefing, shout on their phones in the cockpit while engineer and crew are having a technical discussion, they hover over you, yes I have had three ground staff from one airline in the cockpit all watching me fill the log book in while comments such as , "we are going to lose our slot" are bandied about. CRM/SOPS/Human factors seem alien to them. "Get the brakes off" they say, not realising the air bridge is still attached, tow bar not connected or that the crew are part way through a check list which if interrupted could cause a vital step to be missed. It does not surprise me that things get missed, I have done it myself, fortunately the holes in the cheese didn't line up, the next level in the procedure caught my error, but it can happen oh so easily when corners get cut due to 'norms'.
However,
When I worked in the US the procedures where very tight. If engineering was still working in a plane when you arrived at the plane, you made a 180 and waited in the terminal. We even had placards that rested on the throttle quad to warn pilots not to touch anything.
Must have been a while ago, its hard enough these days to keep the crew out of the flight deck even with the big 'DO NOT TOUCH' placard on the throttles. I actually had one US Captain, walk into the flight deck throw the placard out the door and start the APU! No regard to anyone's safety.
Be safe everyone, and slow down.