That is correct it is a matter of public record as to the real estate owned by anyone.
that is why Pa mls has changed its policy and puts the selling agent information
and not the purchaser info. in those records. Is she a realtor or using someone else's log in. That is unethical. but you can go into public records. I agree I think that is a violation of company policy if she is looking at the sites while at work. Go that route talk to HR.