I had the same thing happen to me the other day. User 899900.... in New York had an art on Day 1. Sadly, it helps no one except temporarily the AI. Most first time players barely know how to move troops let alone what effect an Artillery could have in the first hours of a game. One art, really no big deal, especially if you can't steal it. If you could steal it, then that might be a gamechanger.
Also Northern California has a ton of troops Day 1. On Day 29, they have a crazy amount! Be prepared to be attacked by 200 AI. If you want to fight them, make sure you have a Level 4-5 fort with some art, tanks, and troops and let the AI melt into Bytro death. You lose 0, they lose 250,000.