Any company that is dumb enough to believe that using your mother's maiden name is a secure piece of information is a company that doesn't know much about security. Do you REALLY want to trust them with other, private information?
Information about your mother's maiden name is easily available from a variety of public data sources, including: your birth record (which is public information in the United States), newspaper articles (which can easily be searched online), several online genealogy databases, and many other sources. In short, using your mother's maiden name provides NO SECURITY at all.
Shame on any company that asks for your mother's maiden name "for security purposes."
Actually, the companies that are stupid enough to ask for your mother's maiden name don't care what you tell them. All they want is some word that you can easily remember when needed, such as when you need to recover a forgotten password or something similar. You can give them a real name or a fictitious name. The companies don't care. It doesn't even need to be a name, it simply has to be some word that the company can place in their database and that you can remember when needed.
When any company or web site asks for my mother's maiden name, I always reply:
I can easily remember that name when I need it and it doesn't create any security problems. While I normally refuse to do business with companies that ask for my mother's maiden name "for security purposes," a couple of times I have used Fudpucker and have never had a problem.
I don't think my dearly departed mother would mind.