I carry Doug's whistle everywhere except the shower and the bed, on Gorilla fishing line around my neck.

Why? Because it's louder than me, more piercing than me, more noticable than me, carries farther than me, and I can blow it for a lot longer than I can yell.

And it's completely unnoticable and of no inconvenience whatsoever to have it, so why not?

And my dog comes to it.