There's lots of chix whose slit you can't see from the front. In my experience, that doesn't make them less trustworthy than chix with front facing slits. Of course, premium chix aren't very trustworthy to begin with.
In keeping with your original statement - "some girls have their slits entirely on the bottom of their bottom. They could walk down the street without even wearing a thong and not really show anything at all" - I'd encourage all chix to do that so we could judge properly.