Yea, my script has that capability.
I disabled it for exactly the reasons you're seeing. There are way too many words that use portions of other words. The ONLY true way to check such things is with the human eye...unless you really want to drive submitters nuts.
And just for the record, I do indeed check for such things. Once you get used to it, the human eye is pretty fuckin quick
Virgo is right on the mark. Other than the obvious ones mentioned in this thread already...words like girl, teen are fine. It's when you combine those words with young, you run into problems.