Why would I presume this to be any more accurate than "can't arrest somebody for a sabotage without letting him to execute the deed" was?

If sabotage is so easy to perform without detection, why aren't motivated actors doing more of it? It's certainly not a lack of motive at play, here.

Humans make mistakes. The saboteur can't afford any. The cops only have to get lucky once. And these are the folks who mix up "SIM card" with the game "The Sims" (https://www.washingtonpost.com/video-games/2022/04/26/russia...).

https://en.wikipedia.org/wiki/Double-Cross_System

> After the war, it was discovered that all the agents Germany sent to Britain had given themselves up or had been captured, with the possible exception of one who committed suicide.

Not a single successful agent in five years of war.