Will people know that I am in the U.S if they call my Canadian (Rogers)...

[angela]

...cellphone, even if I do not answer? I went to the United States for vacation, but didn't tell my family I went. I kept my phone on, and they called me half through my trip. I am wondering if, just by calling me they were able to know where I was. I didn't answer the call...but I'm wondering if maybe as they went to dial my phone number normally they were prompted to add a 1 to the area code because it was long distance or something like that. Thanks for your help! And I am with Rogers