Can a person not get hired just because they are in the Reserves or National Guard?

I have to ask this question because it just happened at the job I work for. A lady that works there told me that her daughter was coming to work the following day. The next day, I was asking her about the daughter because I mistakenly thought this other girl was her, and she told me that they wouldn't hire her because she was in the Reserves, and it was likely she would be going to Iraq, and that someone else who really needed a job could get this job. I thought that was so funky. Look, I just want honest answers here. No opinions. If you got facts. let me hear it.