> avoid even the appearance of impropriety

the real world standard is don't do anything that knowingly or intentionally violates the law or your employers policies.

anyone can falsely claim that what you are doing is wrong but as long as it doesn't break employer policy or law then they are wrong.

in the corporate world it would be suicidal to "avoid the appearance of impropriety" because your competitors will slaughter you while they are following the letter of the law.