Wife fired for interviewing

My wife works for a company of about 50 or so employees. Over the last 11 months they've turned over about half of the firm. Needless to say, the work environment is less than desirable. So, she decided to look for a new job. She found an interesting job and has been on 4 interviews (on her own time) with this company and her sense is that an offer is forthcoming in the next week or so. So far so good.

Well, it turns out that her prospective employer passed her resume on to their accounting firm and the accountant knew someone at her former job. He took it upon himself to call her former company and talk to his buddy there about my wife. Apparently, he had good things to say about her. The rub is that my wife's current boss' husband works for her former company and caught wind that someone called and asked for a reference. He told his wife who is my wife's boss, who in turn, told one of the partners. He called her in, said that they heard she was interviewing and fired her.

I can understand the actions of everyone involved. The accountant figured he'd call his friend for an opinion on my wife, her current firm made and emotional decision based on the attrition, etc. However, my wife is now unemployed because of someone's lack of discretion. She consciously avoided listing any employees from her previous job as references and instead listed former employees and the accountant called over there on his own to talk with a computer guy.

Does the law prohibit this type of freelancing on the part of a potential employer? Again, I know that their was no malicious actions here, but I believe that they should be made aware of any legal missteps they may have committed. Thanks.