yes, I thought about it. but how many names can you save/check like that? won't it be a tedious process? Also, what about names from Europe, muslim names etc?
You build a database and program to match the names to a list. The database would contain only a few thousand records which would be easy to manage and speedy. Very simple process for a programmer. None of this work should be done manually.
For names you don't know you keep using other means to dig further. But no matter what tools I would use, matching names to gender would be highest weighted procedure and the first thing I'd try. Of course, there would have to be second and third things to try too.
Remember, these guys didn't say they were 100%. Who even knows what their definition of "pretty accurate" is.