I wholeheartedly agree.
Always try having my passengers helping by looking out.
For some reason the controlzones and TMA's is the place where I relax when it comes to looking out, knowing ATC will provide traffic information if relevant, stressing a bit more about it just outside controlled airspaces around airports. where the density of VFR traffic is higher, and everyone are converging/diverging from the airport, tuning their radioes etc.