Question: why abbreviating 2020 is bad?
Answer: Don't abbreviate 2020 on checks and documents. ... The reason is simple: This year's abbreviation, “20,” can be easily amended to appear as if it was dated in a different year. For example: A scammer could change a check or document signed 1/3/20 to read as if it was dated 1/3/2019 or 1/3/2021.