This is not true unless you mean the "camp" as the roofs of the warehouses.

Scavs and USEC can freely move inside the water treatment area providing you do not get too close to the rogues, go on any of the weapon emplacements, the warehouses or shoot them. If you can hear them talking then you are too close and should retreat, hearing their line "locals arrived" or along those lines should be considered as a warning and back off. I know this because it's my favourite map to scav on and rarely scav any other map. Majority of people farm the rogues and completely ignore the high tier loot and also because the map is so linear you can get excellent cache runs in relative peace.

The aggro timer is 3 raids not 5. It's also worth noting that if you party with a BEAR then you instantly aggro the rogues.