Windows security is notoriously bad and awful and easy to bypass. It “keeps honest people honest”.

As long as they kept Biden’s laptop offline – that is not hooking up to the NTP (Network Time Protocol), they’re free to change the date/time as they wish, add whatever file they wish showing whatever times they wish and it’ll all show up as perfectly normal with zero evidence of anything other than what they would like it to appear.

This isn’t even difficult stuff; grade-school / middle school kids learn to do this stuff to bypass game security stuff like winning time limited tokens in a game by going offline, setting the clock back a few days, doing the thing that gets the free tokens, bringing the date back to now, then coming back online.

This works on games that are both online and offline, not with games that are online-only. But it’s an example of an easily manipulatable thing