Maybe to people in this forum, but I would think in a modern, urban setting people would just think "books & computer". Most people don't carry survival supplies and they are shocked when they encounter someone who does. I doubt in an emergency they would suddenly start thinking anyone with a backpack is carrying survival supplies.

Here's an example. What do you think when you see a man wearing a waistpack in the front of his body? The average person probably thinks "dork" but I bet a lot of pople here think "concealed handgun".

-Blast