Same as cell phones, I'd guess. I used to love wifi for phone calls, before unlimited rates became realistic. If mfg's allow calls and data, they'd have a winner, as they wouldn't charge as much. (WIFI was FREE. The plan was a few dollars a month)

The only drawback was the phone. It roamed for a better source every 5 minutes, and you couldn't turn it off. Real bad when using WIFI with a strong cell tower nearby.

Used to drop calls every time there was electrical interference in the office (2400mhz Cordless Phone. MFG REMOVED)