Where did I say anything about trading only a few positions or not having diversification? I just checked and I currently have 67 positions and was over 100 before the June monthly expiration -- mostly short calls and puts. I like diversification. But I never worry about auto-liquidation because I don't let my leverage get so high that any 20 point jump in the VIX will cause a liquidation and force me to dump positions at the worst possible time.
I'm talking about portfolios where any kind of jump in the indexes won't cause significant losses. Leverage is almost irrelevant in very balanced portfolios.