Regarding Nathan Vilas Laatsch's alleged attempted espionage, see the U.S. Department of Justice's press release dated 29 May 2025:
https://www.justice.gov/opa/pr/us-government-employee-arrested-attempting-provid... The release notes "In March 2025, the FBI commenced an operation after receiving a tip that an individual — now known to be Laatsch — offered to provide classified information to a friendly foreign government."
Although not stated, I think it's highly likely that the tip came from the government that Laatsch approached. Such was the case with
Jonathan and Diana Toebbe, who attempted to sell information about U.S. nuclear submarines to Brazil: the Brazilians promptly informed the U.S. government about the attempt, and undercover agents proceeded with a sting operation, with the cooperation of the Brazilian embassy.
The choice for a government friendly to the United States is an easy one: why risk taking an American walk-in as a source when in all likelihood, it may be an undercover U.S. agent testing how that government would handle such a situation? Why risk the harm it could cause to bilateral relations?
In Laatsch's case, it seems that the U.S. government was on to him essentially from the get-go.
So, with respect to polygraph policy, it would seem that fear of the polygraph did not deter Laatsch, and if he was polygraphed during the approximately two months from the time he approached the friendly foreign government until the time of his arrest, then DIA's polygraph unit was likely briefed on the situation.