dependent on I140

I am on an H1B with I-140 approved. My wife is on F1 visa which we got stamped in August 2008 in India. We filed the I140 in Sep 2008 WITH HER NAME AS DEPENDENT. This got approved Nov 2008.

We are planning to goto India. Both of us dont need any visa stamping in this visit abroad. However we are worried that the border security may have problems with my wife being on F1 and her name as a dependent on my I140.

Questions

Is this really a problem considering she is not the primary applicant for this I140.
Do the border security actually has all the information about my I-140 filing and my wives name being on that.
If she is refused entry,Is she sent back to India or we can apply for H4 visa in Canada. Can she be denied H4 visa in this case?