While rarely prosecuted for individual use, using a cracked registration code violates copyright law (DMCA in the US, CDPA in the UK). More importantly, if you use a crack professionally, your studio could face audits.
: Many players seek registration codes today because the original payment gateways no longer exist. To play the full game on modern hardware (often via emulators or compatibility modes), users feel compelled to find "legacy" codes shared on forums. The Security Risk airxonix registration code