Beacons can't send push notifications. Beacons are equivalent of light houses in 2.4GHz spectrum. They just keep broadcasting their presence and send their UUID. Everything else is done via the apps installed on your device.
(That's, coincidentally, is also why a lot of dream scenarios for beacons can't take off - they literally require you to have an Internet connection and a vendor-specific app on your phone to do anything interesting, which is not something you can expect of people outdoors. Facebook has a really good chance of making some of the beacon ideas work, because a/ almost everyone has their app, and b/ it's an app that people actually want to use outdoors, and they power up their mobile connection for that.)