If you didn't see the accent mark, how would you have pronounced it?
More often than not people can't/don't type accent marks so when my name is typed, the accent mark is usually not included, so most people say it wrong.
[Named after Adam Walsh's mother (whom Code Adam was about) and John Walsh's wife (host of America's Most Wanted). My parents weren't trying to be oh-so-unique, lol. My dad's name starts with "R."]