> Right, which is where reasonable doubt comes into play: if the video was months ago it's completely reasonable to forget a password -- if it's two hours later they have a much tougher case to make about spontaneous amnesia.
You're confusing less likely with unreasonable.
A pass phrase long enough not to make the whole question irrelevant is hard to remember.
You may have it in short term memory until it gets displaced by "oh crap I need to hire an attorney and a bail bondsman and call my boss and explain this to my wife" type issues. You may be able to remember it sitting in a familiar environment surrounded by your stuff but not in a jail cell without any of those cues.
It's completely reasonable to forget something you knew five minutes ago. It happens all the time.
Haven't you ever walked into a room and been unable to remember why you did? And that isn't 128 bits worth of context-free random data.
> "Did you know she was under 18?"
> "No your honor, I forgot, it had been a few weeks since I saw her ID."
I'm not sure this is making the point you want it to. The real targets of statutory rape laws are pedophiles who rape eight year olds, and in those cases it isn't a question of memory. You may not have remembered whether the child was 8 or 9 but you couldn't reasonably have thought they were above the age of consent. Which is why nobody objects to putting those pedophiles in jail, or to the laws that make it happen.
It's the cases where there could be a legitimate confusion that create exactly this problem. You can't tell if someone is one year above or below the age of consent just by looking at them, which is why those cases are extremely controversial.
How is it absurd that you could forget someone's age? Do you know the exact age of everyone you've ever been to the birthday party of? You probably knew on the day of the party.