The same visible role can have the opposite effect
A Good Cop display tells you what the resident appears to be, not which counterpart is behind it. In the ordinary pair, the real Good Cop is normally good and Bad Cop is normally evil. Their current alignment determines the copied conversion result.
This makes the source the first unresolved question. Testing a convenient-looking ability on a supposedly safe target can introduce a new evil-aligned target if the source was the counterpart.
Use the pair as a constraint, not an automatic identification
The official descriptions state that each counterpart is in play when the other is. That makes it useful to look for an arrangement containing both in an ordinary case. It still does not label the two addresses for you.
Compare independent clues about the residents’ actual properties. When an observation contradicts the ordinary pair, check whether the case-generation choice or active rule changes the baseline before turning the conflict into a new universal rule.
Do not rely on an unverified workaround
A current player report describes adding Bad Cop through a special chaos-ticket choice without seeing a Good Cop, but the read thread has no reply establishing a cause or fix. This page does not call that a confirmed bug or prescribe a workaround.
For a normal pair, the actionable step is still clear: establish the actual source before conversion, then update the target’s current alignment in your notes. If the game presents a rule that differs from the ordinary description, reason from that actual rule.