How to penalise smurfing without penalising risky early attack strategies?

You guys say smurfing should be penalised, but how can you do that without penalising or basically banning early attack strategies? Let's say I take all my villagers for a villager fight against yours (villager rush), or TC attack, or militia attack, all in dark age. I'll probably lose against any decent player with that, especially if badly executed. How can you then be penalising smurfing without disabling valid strategies in the game (even if not optimal)?