I remember the last time he said not to short Tesla. It was right before/during a secondary offering where the stock went through some rough times. What he says literally doesn't matter to Wall Street one way or the other. Honestly, I can't imagine Tesla going much higher unless people do short it. With my tin foil hat on, I think Elon knows that the best thing is for history to repeat itself. Let a massive amounts of shorts come in before Q3, show a GAAP profit, tons of demand, and increased guidance (which judging by vin numbers looks like it's going to happen), and watch the stock double again.
In fact, I wish Elon would have simply said "I would short Tesla right now, the valuation is crazy". He is being too nice. I want to shorts to make Tesla another billion dollars.