"Matt Barrow" wrote in
:

ATC's job is separation. If they catch something, that's dandy. As
such, if a passenger catches something, that's dandy, too.

Safety / Security is in layers :-)

Note, I said ATC was a safety net, not their job for ensuring our safety
EXCEPT in IMC where we depend on ATC to maintain seperation.

Under VMC, it's our job to ensuring seperation, but ATC would be our safety
net should we miss something. Just like passengers spotting another plane,
always nice to have that handy, though IMC that's not possible (plane
spotting that is).

Allen