[stephengillie]

Retail stores will use this to prevent "showrooming" - where a person goes to a store and looks at something, then buys it from Amazon with their phone.

Ok, so people will still buy from Amazon, but they'll have to leave Best Buy first.

[eshvk]

Isn't it illegal to jam cell phone reception deliberately ?

[greenyoda]

It's illegal to jam cell phone reception by transmitting on frequencies that are allocated to the cell carrier. I doubt it's illegal to passively prevent radio waves from entering your own property.