Well, he was giving advice for 300-turn games, and set that bar at 100 turns then no new cities... so that's the part of his opinion I was disagreeing with. You can always expand into people who won't hate you... or you know, have some diplomacy. More than that, if you're preparing to expand wide and peacefully, you can use your earlier cities to wall off areas for future expansion. Expanding has never gotten me into a war when I didn't want it (although, it is a good way to get into a war you do want also). It's not random. It's never "expand and you'll have x% chance to start a war!", if you know the AI interplay, and have your diplomacy down, you'll know exactly where you can expand into without triggering war, where you can expand to and then have to do certain secondary actions to prevent war, and where you absolutely cannot expand into without triggering war. If you don't want war, don't do the last one, but take the first two types of opportunities.