Ignorance of the law excuses no man; not that all men know the law, but because ’t is an excuse every man will plead, and no man can tell how to refute him.

The rule stands not because everyone knows the law but because the excuse would be available to everybody and impossible to check. Some standards have to be absolute for practical rather than fair reasons, since any exception that cannot be tested will be claimed by all. It is a hard rule with a sensible cause. The same logic runs through deadlines, agreements and most places where people want their circumstances taken into account.

Where you are relying on not having known something, assume it will not be accepted. Find out what applies to you before it matters, in whatever corner of your life you have left vague.