1) The US Government wanted to maintain the secrecy of the program.
2) Giving the data to a large number of border guards would have increased the chance of its dissemination.
3) It would be unnecessary to show her the data to refuse her admission to the US and showing her would violate #2.
4) She would not be a valuable enough target to expose the fact that the US had the data.
Additionally:
It is much more likely that if the border guards were using the NSA data, they would simply receive lists of those that could not enter. She would have probably been a target for that since she was trying to obtain work in the US illegally.
Alternatively, and even more likely, boarder patrol could have searched public websites for her name and seen her occupation and the rest could have been an exaggeration.