When I was in the market for backpacks, they only had the R series backpacks. Now I see they have the R series as well as a Bug and bumblebee setups which are very similar in shape and function... unfocused bag is in their "video SLR" bags with side access pouches, am I correct? That pack, I would assume would be much easier to notice however with the R series and bug and bumblebee... There is a rear zippered access that allows access JUST to the camera area. Those backpacks, in a busy situation, maybe even in a stadium, or amusement park, or anywhere where there are lots of people and people running or bumping other people may not be uncommon, and with access directly behind you, unless you got eyes in the back of your head, it may be easy to ignore vibrations or whatever of someone opening your pack and yanking your bag open and running. Then you get the split second thought of running after them with a half open backpack in which other lenses and accessories can fall out and or break, or zip up your bag quickly and lose a second or two on the runner. I personally dont know and haven't tested this theory because I didn't buy this bag. It could be easier to notice than that, however I really dont know first hand.
My lowepro bag fits more gear than my pelican hardcover 1610 case, however, is it perfect, no. The tripod/monopod holder is in the rear, and the thing sticks out over the back, especially with a full size tripod. All you need is to attach some pots to it and you have completed the homeless transient look. It doesn't look like a photo backpack, it looks like a regular backpack so you may get more attention of security where backpacks may generally be frowned upon, such as stores/shopping centers, concert venues, etc... All the foaming adds more insulation making it a very sweaty bag on hot humid summer days...
Go to the store, try some out, and find one that suit your needs. =)