I'm not sure why asking a perfectly simple - and in the light of the above example which shows there is a difference in how Glass and a hat might be positioned, still perfectly reasonable - question (to which I do not have a preconceived notion of what the answer might be) deserved to be met with such a sanctimonious response.
Have you tried Glass? Did you think it blocked your vision less severely than a baseball cap? If so, say so, and I'll be more informed than I was.
With the cap on, looking straight ahead, the bill blocks the top half of the display. The cap itself blocks much more than the GG display which is transparent. At least on me.