The rules are plain - under RAS achieve standard separation between participating traffic and information (and avoiding action) against non participating traffic in order to resolve the confliction. How does IFR or VFR modify these requirements?
It doesn't. But after reading 10W's write up it's probably a good time to clarify what may have been missed in the rest of what's been written.
If someone's asked for a RAS - they're the one that gets vectored around the sky. If someone's asked for a FIS then they're the one that gets left alone. To go back to Flowers point - you can ask the VFR/FIS traffic if it doesn't mind not going above a level to achieve standard separation aginst your IFR/RAS, but that's as far as it goes. It's their choice, their decision on flight rules and service.
Sweeping statements against their airmanship for choosing that service and the freedom of operation it gives them are out of order - I say that both as an ATCO and a pilot.
And - for all those people who try and vector VFR traffic for their own aims a little reminder. The reason RAS is
only available to IFR traffic is because under vectoring it's possible the traffic may be out in a position where it may go IMC. Do you really want it on your conscience that you vector a student or inexperienced pilot into inadvertant IMC - someone who's always been told not to question ATC and follows your instructions blindly. When they lose control and go spinning out of the bottom of that cloud who's fault is it going to be really?
NorthSouths comments should hit home here. You have no idea of qualifications on the end of the R/T - he could quite easily have been a low houred, newly qualified PPL rather than an instructor. This should be in the back of every ATCO's mind, both civil and military, of every aircraft they work.