Who “they”? Security services are not the hive, It’s not like everyone knows everything pr never misses anything. Or do you think it’s like a game where you unlock the “passive listening device countermeasures” technology and suddenly 100% bugs across the country are found and new bugs can’t be planted?
Why do you think it works like that? They know what it is and how it works, so they know what to look for.
Who “they”? Security services are not the hive, It’s not like everyone knows everything pr never misses anything. Or do you think it’s like a game where you unlock the “passive listening device countermeasures” technology and suddenly 100% bugs across the country are found and new bugs can’t be planted?