Tesla has placed a strange restriction on its forthcoming self-driving car technology: Customers who will not be allowed to use it to work for ride-hailing companies like Uber and Lyft.

The rule is listed on Tesla's website, and was spotted by Ars Technica's Jonathan Gitlin. "Please note also that using a self-driving Tesla for car sharing and ride hailing for friends and family is fine," it warns, "but doing so for revenue purposes will only be permissible on the Tesla network, details of which will be released next year."

(The Tesla network is going to be a ride-hailing/taxi network run by the electric car company, though it has yet to officially launch.)

Tesla is effectively telling its customers that even if they buy its cars, they can't use them in a way that would benefit its competitors.

The prohibition raises interesting questions around ownership: Does Tesla have the right to tell people what they can and can't do with their vehicle after they purchase it? And even if the contract permits Tesla to place these kinds of restrictions, will people wade through the legalese and realise it before buying the car?

Tesla founder Elon Musk. Reuters/Mike Blake It's not clear how Tesla intends to actually enforce this ban. The company has got no way of knowing if a driver is using a ride-hailing app, rather than just taking lots of short trips from spot to spot. Will it monitor all customers' journeys to look for suspicious patterns? And what action will it take against offenders if it finds them — sue them? Deactivate their self-driving capabilities?

Tesla's website specifically mentions ride hailing, but the term "revenue purposes" suggests a broader application of this rule. It could feasibly be interpreted as meaning the autonomous driving technology cannot be used for other commercial purposes, like deliveries.

After all, Uber is branching out into delivery services with UberRUSH; it's an area that would also make sense for Tesla to explore with its Tesla network.

Tesla did not immediately respond to a request for comment.

Here's the full section from Tesla's website on self-driving tech: