Ryan Patrick O'Hara
Veteran
Using a slate you roll for longer
waste time on set while the assistant gets out of shot
risk them hiding somewhere where their reflection or shadow is in shot and not noticed until the edit
tire out camera operators doing handheld with big rigs or steadicams
fry your talent hanging around under hot lights forcing more make up touch ups or breaks to cool the room down and put the aircon back on for a bit
directors who storyboard stuff never* board enough cutaways and dont want to do them because they are not part of the 'schedule' - causing expensive pickups or continuity problems down the road
lose windows between aircraft noise or cloud movent
fill up more cards - seriously sometimes 50% more digital data
heat up your camera chip and create noise
flatten your batteries
create longer transcode times
fill up more hard drives
have one less person on set who could be holding a reflector, downloading cards or making you a coffee
Or if they are employed by you they could be back in the office marketing your company or doing some boring tax s**t for you
because the takes are written in pen a dozy assistant can mess it up by losing count
in the edit sometimes seeing an opening frame is quicker to navigate than a bunch of frames that all have a slate filling the frame
in the edit longer clips take longer to navigate
All solved by having a good camera assistant AND/OR tail slating.
I enjoyed your foray into being the devil's advocate, but honestly a bad _______(anything) will hurt a production. Please don't discount the importance of the slate or 2nd AC only on the sole basis that the 2nd AC is potentially horrible at their job. 2nd Ac's don't make coffee or do your taxes. They don't fall asleep or waste time. You should immediately fire anyone who does. It seems your 2nd AC's aren't proper 2nd AC's but just a crew member wearing the hat of 2nd AC... perhaps the reason they fail at their job and do all the horrible things you have listed above, which are not common place on set.
I don't think the slate is always needed, but I don't think it is ever a negative impact, unless the person who wields it is unprofessional.