Running away with profits is never foolish, just sub-optimal!
If timing is right, it would be optimal, especially for those who bought on margin. I for one fall in that camp. I unloaded all my margin TSLA shares earlier today for a decent profit and plan to buy back in later at a discount. The margin loan eats into the gains if holding the large amount of shares over time if TSLA trades sideways. But my cash bought TSLA shares are going nowhere. They're gold and won't be sold anytime soon.