We've now entered the year 2020—but don't abbreviate 2020 when signing your legal documents. Police have warned that anyone signing important documents or checks with an abbreviation of 2020, i.e. "20," could put themselves at risk of fraud. They recommend writing out the date in full, as 2020, on legal documents and checks.

Why not abbreviate 2020?

By writing out the date as 01/01/20 (January 1, 2020), the date can be fraudulently changed to 2019, 2021, or any other date in this century. Instead, make sure when you're dating documents in 2020 that you write the year out in full, to protect yourself against fraud.

This is a problem is to do specifically with the year 2020, as abbreviating 2019 as "19" could only be changed to a date in the 1900s and abbreviating 2018 as "18" could only be changed to a date in the 1800s.

legal documents
Legal documents including income tax forms.SCOTT OLSON/GETTY

Changing a document's date from 2019 to 1999 would be a lot more difficult to fake as it would be a 20-year difference, compared to changing a document's date from 2020 to 2019, which is only a one-year difference.

But abbreviating 2020 to 20 means that a criminal could write two numbers after the 20 to imply that the document was dated before or after it actually was.

This advice has been shared widely on social media, and police and a county auditor have also recommended writing the date out in full.

Dusty Rhodes, Hamilton County Auditor, tweeted: "When writing the date in 2020, write the year in its entirety. It could possibly protect you and prevent legal issues on paperwork. Example: If you just write 1/1/20, one could easily change it to 1/1/2017 (for instance) and now your signature is on an incorrect document."