Key disclosure

[subwoofer12]

Let's say for whatever reason Uncle Sam wants the password to decrypt my wallet

There's been a few court cases on this
Appeals court: Fifth Amendment protections can apply to encrypted hard drives
United States v. Doe

Can the government force us to disclose our wallet passwords?

And what if you just claim you forgot it?  
This was almost addressed in United States v. Fricosu but she was stupid and had all her passwords stored in cleartext  

[Bitware]

The question you should be asking yourself is, what is the exact amount of torture and/or prison time you will endure before you will disclose the key?

No criminal nor judge will believe that you don't know/remember the key if they know it exists, so perhaps it's best to prevent others from knowing it exists in the first place. We call this OPSEC, or OPerational SECurity.

[Cryptology]

"Plausible deniability" they call it.

[Snorek]

Unless you are like total hardcore badass and don't care about anything anymore there is literally no no you could keep vital information like your passwords to yourself.
What will happen is - Uncle Sam will offer you deal you cannot refuse and you will be happy with it, because if you refuse rest of your life will be ruined.