ETA: Secondly, I want to reply to the comments about Trayvon ducking onto someone's porch to get out of the rain. This is a neighborhood of condos, right? In my experience, condos don't tend to have a lot of distance between the sidewalk and the porch/door. My mom lives in a condo and I can move from the sidewalk to the shelter of her front porch in a couple sideways steps. It's not like Trayvon had to travel down a driveway to get onto a porch. Step to the side, slip on the hood, decide to make his way home. IMO. (if we are not talking about condos, let me know. It's been hard to keep up)
I wonder if Trayvon even went under the porch of an individual townhouse. The clubhouse for the development is right at the front entrance, and where GZ first said he was calling from. It would be natural to step under the porch area of the public building to take shelter from the rain and that should not have been thought to be suspicious.