Absolutely true, but this is also possible with just about every other technology today. "Bad Apps" can report information about Beacons, GPS, or any other sensor on the phone they have access to.
Hm, maybe not so easily with other technologies. GPS is a passive thing and you can select which apps can use it. Beyond that or outside of your phone nobody will be able to register your location.
WiFi is active and yes, wiretapping is possible, at least for locating you. Hardware/software for doing this though is not readily available as far as I can tell.
Finally, iBeacons: very simple software running on a passive BLE device that simply records all BLE UUIDs passing by, that's all!
