Can someone with a single entry B VISA go visit Canada?

[bbli]

My sister is coming to visit me in Nov. She has a single entry B Visa. I would like to take her to Vancouver, Canada for a visit since it is not too far from where I live. She doesn't need a VISA to visit Canada because we are from commonwealth country. My question is, once she leaves the US/Canada border, can she re-enter USA? Some people say the border officials won't take away her I-94, so she can re-enter with a valid I-94. Is it true? Is there any risk?

Thanks in advance.

 

[rocky7]

Yes, but make sure you don't lose the i-94 and do not give it to the Canadian Officers!!!