I wonder if there is a correlation with people who disregard or who seem unaware of placards in the cockpit.
One recently where, right beside the tacho, was a placard stating max rpm for aerobatics was 2600 but "we use 2700".
And earlier, "I didn't know about the placard stating the use of aileron for spin recovery."
Plus my standard observation in pre-licence checks in PA-28: placard stating that unused seat belts are to be fastened.
Local pilots have been known to leave the dipstick loose so creates a real mess when the aeroplane is turned upside down. I see that one flying school has added their own placards to secure the dipstick before flight - if pilots can't think of screwing it in after putting it back in following check on oil quantity then I don't see that a little placard will remind them.
My old man used to say: "Don't trust anyone who can't spell, they don't know their own limitations."
I used to get job applications from graduates who used the spell-checker resulting in their name being spelt incorrectly. My customer rejected electonic reports and data with incorrect spelling of aircraft component names and wrong part-numbers as it could result in costly fixes to documentation to correlate certification data. With so many good applicants for an engineering job it didn't take much to ignore some-one's applicaton.
Similar very competitive situation wrt commercial pilots however I agree that there are more important skills (but getting off topic there).