ACW335
It is your responsibilty as captain/pax to keep a good look out going at all times.
This is true, but remember that some quite heavy metal may be in the airspace, e.g. a Canadair Challenger proceeding quite legally at 250kts.
If you get blown away by wake turbulence, then airlaw may not be such a great consolation.
I had a 'close encounter' (i.e. intended and advised by ATC) with a 727 a few years ago, in controlled airspace under radar control and it did make me consider how good viz is in jets and turboprops, since the crew never saw my a/c even though we saw them VERY clearly.
Still, its your call.....