[jacquesm]

That is why the real date will be spelled out, typically like this: January the twentieth of the year two thousand and twenty or something to that effect. We're talking legal documents here, they don't take chances with those. The date shorthand is just that: a shorthand.

Any serious contract / deed / legal doc I have signed so far has followed that convention, the century being the optional one. The fact that there are always multiple signed copies of such documents, other supporting documents (communications, email) and that fraud in writing is punished quite severely seems to have kept me safe so far.