Tesla opening its Supercharger network to rivals could be a brilliant marketing move from a company that famously doesn't advertise — with one big risk

• Tesla plans to open 3,500 of its fast-charging plugs to all electric-car owners by the end of 2024. 
• Until now, Tesla's Supercharger network was only for Tesla owners in the US. 
• Some experts say the plan could boost Tesla's brand and ultimately help it sell more cars. 

If you own any electric car that isn't a Tesla, you've probably gazed longingly at the brand's sleek Supercharger stations, which are common and famously easy to use, but historically off-limits to outsiders.