Today I call in my old friend Trigger, the handsome chestnut horse. This post comes with the usual trigger warning: Possible neigh-saying ahead.

Serial entrepreneur Elon Musk has made the bold prediction that your driverless car may soon be able to take you from New York to L.A. Soon, as in maybe two or three years from now.

Mr. Musk is CEO of Tesla Motors, which builds electric vehicles few people care to drive. He is also CEO of SpaceX, an exploration company, and the largest stockholder in SolarCity, the country’s #2 provider of solar power systems.

Notice the common thread of government subsidies. The Los Angeles Times reported last year that Mr. Musk’s main three companies have received $4.9 billion.

The Times also quoted Dan Dolev, an analyst at Jefferies Equity Research: “He definitely goes where there is government money. That’s a great strategy, but the government will cut you off one day.”

Later in the article: “A looming question is whether the companies are moving toward self-sufficiency – as Dolev believes – and whether they can slash development costs before the public largesse ends.

The bigger question is whether such largesse ever will end; that debate is for another day.

As for driverless cars, I totally get the sweeping visions advanced by Mr. Musk and other parties including Google, Government Motors and Ford. As for long trips, the devil might be in the details. Suppose the passengers urgently needed to visit a filthy gas station restroom? Could they seize control?

Perhaps these questions will become moot when a driverless car wipes out a family of four and development stops for a generation.

Meanwhile, I’ll not question the sincerity of Mr. Musk, other than to call out his optimistic timetable. It’s horsesh**. Come by my stall for a whiff.