How Effective Are Keychain Locators for Those Who Can't Whistle?

[Moonbear]

hanging from the front door knob.

Adds to list of things to give tribdog for Christmas next year:
keychain that beeps when you clap

 

[Chrono]

Adds to list of things to give tribdog for Christmas next year:
keychain that beeps when you clap

My mom just got not one, but two of the ones that beeps when you whistle. The thing is her nor I can whistle very well.