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I suppose in these cases it's either bots, or people whon don't know anything about the game but bought/rented 2 cards and are playing them only.

I've seen a fair few instant surrenders when green isn't available. I think a lot of people are using llamakron as a (unfortunately very effective) krutch.

That's possible, and it might even be cost effective if they do this all day or automate it with a bot.