Spitoon,
The pilots of all flights are required to keep a lookout. That is regardless of what flight rules they operate under.
The rules for avoiding collisions (give way rules) also apply to all flights.
Thus a VFR flight and IFR flight on a collision course means that the pilots of both aircraft are required to comply with the requirement to look out and comply with the rules of the air for avoiding collisions.
That is another reason why controllers tend to add in some separation in class D between VFR and IFR flights.........it can get a bit embarrasing if we as an IFR flight turn towards another IFR flight in order to avoid (give way to) a VFR flight.
Of course when we are in cloud, there can't be any VFRs in there with us can there?
When operating into an aerodrome outside controlled airspace, we considder all instructions to be advisiory even if procedural service because being told to descend to an altitude may not be a good idea if there is an aircraft unknown to the controller below. Thus we will do what we are told whenever possible but may need to do otherwise.
Regards,
DFC