EA Maxis's claim that SimCity requires an always-online connection because its servers handle most of the game's processing and calculations has been put further in doubt, as a player has managed to modify the game to run offline—contrary to what the studio's head, Lucy Bradshaw, said was possible.
Posting on reddit, a player named UKAzzer modded the game to run offline. He posted a video showing how he could edit the cities outside of the game's very small, limited boundaries—modifying its highways and placing zones. He was also able to disable the fluffed up population counts which have been the cause of many players' complaints with the game's inability to properly calculate RCI (residential, commercial, industrial) requirements.
Most importantly, the modder was able to disable the game's disconnection timer, playing the game well beyond its 10-20 minute time limit which typically sees players kicked out of the game for losing their connection to the servers. Playing the game offline, he showed how his cities loaded quickly and almost instantaneously.
The video, seen below, is a clear indication that the game is capable of running offline without a connection to the EA servers. The only features disabled, of course, are the game's region functions and its online social networking features—ones which many players keen on playing the game alone and offline hardly care about.
Maxis has a lot to answer for, especially with the claim that SimCity will not be able to run offline without "significant engineering." It'll be curious to see how the studio plans to tackle the latest development and whether the company will release an offline mode or if players will be forced to mod the game just as UKAzzer did.