SAN FRANCISCO — It took Hurricane Irma for some Tesla owners to remember that their electric cars actually had more than range than promised on the showroom floor.

When one Florida owner of a Tesla sold a few years ago contacted his dealer to see if his battery's extra range could be activated remotely, allowing him to get away from the sprawling storm, the company responded by quietly maximizing the range on all the applicable Model S and X vehicles.

While this all sounds like an automotive Great Oz bestowing power magically and selectively on its owners, the truth is simpler.

When Tesla sold cars back in 2016 and early 2017, it offered a cheaper version of its powerful electric vehicles by using software to limit the range of the 75 kilowatt-hour battery to 60 kilowatt-hours, thereby cutting the distance the car could travel by about 30 miles.

This limited-range approach allowed Tesla to build one battery, and gave owners the option of paying as much as $9,500 to unlock full power and extend range to as much as 300 miles. Tesla has discontinued that approach, and today makes 75 kw/hour or 100 kw/hour batteries, with ranges of 265 to 351 miles.

Even today, owners of those previous models can pay that fee to permanently boost the range.

Tesla did not offer a comment on the unpublicized upgrade, but in an email to USA TODAY, a spokesperson said that the boosted cars would have their extra range through Sept. 16.

The electric automaker typically uses over-the-air software updates to improve features and monitor telemetry. But its move to improve battery range caused some to wonder aloud whether Tesla's remotely controlled batteries were a good thing.

"If @Telsa can remotely extend battery range can it b maliciously limited too?" asked @mattarrow.

Tesla owners seem resigned to the same sort of fingers-crossed relationship that is familiar to anyone living in the permissions-filled internet age.

"To me, it's like when you agree to use cookies, you know (companies) are following you around but you accept it," says Larry Chanin, president of the Florida Tesla Enthusiasts club, which has 600 members.

"It's the same with a Tesla," he says. "To maximize use of the car’s capabilities you need to keep them on. Only the most paranoid individuals would see this as a Big Brother kind of situation. I like it, makes me feel good. I just see it as an adjunct to innovation and progress."

Chanin says he was contacted over the weekend by a member who was shocked that his 60 kw/hour Tesla suddenly seemed to be displaying additional range. "I had to explain to people what was going on, but they seemed happy," he says.

Omar Sultan, president of the NorCal/Reno Tesla Owners Club in the Sacramento, Calif., area says that the stealth nature of the battery boost was surprising. "No blog post, no tweets from (CEO) Elon (Musk). They just did it," he says. "As for feeling like they're watching over you, it's part and parcel of owning these cars."

Sultan says Tesla does offer an opt-out option for those who do not want their telemetry data tracked, but he doesn't know of many people to go that route.

"You could say there's certainly potential for abuse, but you either trust the company or you don't," he says. "I've heard some people grumble, saying 'Well what am I getting in return for passing on all this information about my driving,' but the answer is a better car. So it's a trade-off."

Follow USA TODAY tech reporter Marco della Cava on Twitter.