People frequently spell my last name with an "r" instead of an "h" and each time I correct someone they apologize. Sure, apparently "Ingram" is more common, but I don't pronounce it that way. Better to ask than to assume. In search of a unique identity, people are looking for greater variation in how to spell their names so that they are indeed unique.
Google your name and see how many of you there are. Imagine my surprise to find other Karen Inghams who are writers, and artists and even work for Virgin Media. No rocket scientists or neurosurgeons. Hmmm - I wonder if that means anything. When you look for images of Karen Ingham, however, I am not there - yet. That is definitely something I have to work on. I can, however, assure you that the half naked woman that appears in one of the images is not me.
So back to names. Even is someone tells you their last name is "Smith", don't immediately assume the most common spelling. With over seven billion people on this planet, chances are really good that there will be duplicates. Good, but not a sure thing.
I think it points to how respectful you are of other people if you take the time to make sure you have the proper spelling and pronunciation of all those you know, both personally and professionally. If someone doesn't bother to know how to spell my name, what else have they been careless about? It makes me wonder and it should make you wonder too.
Remember, you won't lose points with someone if you ask "Could you spell that please?"