Yes ! i agree with you Reese, they also could have moved to another state in the usa, i only looked at the Detroit census because that is where my relative went. They also could have changed thier names.
You dont mention if you know where your Grandmother went, which makes it even harder for you, but dont give up. If i find out any thing that might be of intreast to you i will post it on the site.
Thanks for your wishes