Of course. I myself won a game on XL by quickly placing the Graal in Conflux, and from a screenshot of the 1st obelisk, a guy from the chat found my Graal based on a few tiles of even ground (i.e., it turns out that ordinary ground tiles also have a texture and they can be different). IMO complete nonsense, this crap should be banned everywhere. Or at least make it so you can dig only for fun, without ruining the game with it :D
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Terrain inspection + obelisk = you know where the Graal is. There's no skill or interest in that.
I'm saying that digging up the Graal on XL maps is much harder than on L maps. You need huge luck and a real desire to spend time on it. After all, there may not be just 2 or 3 zones with the same landscape generated, and I'm not even talking about the underground, where it is most often located.