How can you tell when someone buys?

I was asked the other day where I was registered for my baby shower, no where was my response but now I've registered at Babies'R'Us, Target, and Amazon. I was wondering if there was any way to tell whether someone buys something you registered for? This is my first time having a baby shower and I don't know anything about being able to tell if someone buys something you registered for. Is there any way to tell?????