For those with questions or qualms about his gun visibility and his holster, I took a couple of quick pictures to illustrate. I apologize in advance for the lack of color-coordination. I just grabbed my jacket really quick to take the picture. I also apologize for the pastiness of my stomach!
In any case, this is what Zimmerman would have pretty much looked like when he was walking around:
And this is how Zimmerman would have had to have been "flashing it". I would feel silly walking around like this, but that may just be me. This is also the extent the clothing would have to be adjusted for the weapon to be visible and recognizable. It's not just a matter of "Maybe his jacket got pushed back".