few notes

docs/spending-policy.md

@@ -16,3 +16,35 @@ master secret (not a seed phrase anymore). This process cannot be
 reversed, so other funds you may have on the same seed words are
 protected. Once you are operating in XPRV mode, you can define a
 spending policy and know that it is restricted to only that wallet.
+
+## Trick PIN Thoughts
+
+When doing your game theory w.r.t to bypass mode and this feature,
+remember that you should assume the attacker already has your main
+PIN. That's how they know they cannot spend all your coin, because
+they either tried to, or noticed the menus are very limited. They also
+have all your UTXO locations and total wallet balance (because they
+can export xpubs to any wallet and load balance from there).
+
+Therefore, a trick pin that leads to a duress wallet after giving up 
+the bypass unlock PIN does not fool them. Best would be to provide
+a false bypass PIN that is in fact a wipe PIN.
+
+### Unlock Policy & Wipe
+
+We've provided a new trick PIN that pretends to be the unlock
+spending policy pin, so the login sequence is correct... but it
+will wipe the seed in the process. It will be obvious to your
+attackers that you've wiped the seed because the main PIN will lead
+to blank wallet now (no seed loaded).
+
+### Delta Mode and Spending Policy
+
+If, from the start, you gave your "delta mode PIN" to the attackers,
+then when they bypass the policy (after also getting the bypass PIN from you),
+they will still be in Delta Mode.
+
+They could attempt unlimited spending, but transactions signed will
+not be valid. If they try to view the seed words or generally export
+private key material, they may hit many of the "wipe seed if delta mode"
+cases.