Your understanding is incorrect. The government is constitutionally required to disclose information (not just "evidence") which is the hands of the prosecution team which is exculpatory (favorable to the defendant). It gets a bit complicated as to what constitutes the "prosecution team." It would include, for example, all exculpatory information in the hands of the police officer investigating the crime even if the prosecutor never learns of it.
True. Thing is, evidence that there was a 4th Amendment violation from hell would absolutely be required as part of the turn-in, known technically as the "Brady disclosure file".
This isn't just "fraud" or "scam", this is a criminal conspiracy to undermine the constitution.