BIP-352: warn against stopping scan due to wallet policy filtering

bip-0352.mediawiki

@@ -357,7 +357,7 @@ If each of the checks in ''[[#scanning-silent-payment-eligible-transactions|Scan
 ****** Add ''P<sub>k</sub> + label'' to the wallet
 ****** Remove ''output'' from ''outputs_to_check'' and rescan ''outputs_to_check'' with ''k++''
 ***** If a label is not found, negate ''output'' and check a second time<ref name="negate_output">''' Why negate the output?''' Unfortunately taproot outputs are X-only, meaning we don't know what the correct Y coordinate is. This causes this specific calculation to fail 50% of the time, so we need to repeat it with the other Y coordinate by negating the output.</ref>
-*** If no matches are found, stop
+*** If no matches are found, stop<ref name="always_continue_scanning_after_match">'''WARNING:''' The decision to continue scanning (increment ''k'') must be based on whether a cryptographic match was found, not on whether the wallet considers the output spendable or relevant. A match that is later filtered by wallet policy (e.g. dust) must still trigger a rescan with ''k++''; stopping early may cause subsequent outputs for the same sender to be missed.</ref>
 
 ==== Spending ====