Wube Software is famously anti-DRM. They believe that if someone pirates Factorio and loves it, they will eventually buy it. In fact, in 2016, the developers uploaded a torrent of the game themselves to test this theory.
: Most public and dedicated servers have the verify-user-identity setting enabled by default. This checks the connecting player's unique ID against official records; cracked clients with invalid or spoofed IDs are automatically rejected. Multiplayer Methods for Cracked Versions
"Verified" in the cracked scene means "we tested it on two PCs on the same desk for 10 minutes." It does not mean enterprise-grade stability.