Single Spey when providing a RAS controllers have to attempt to achieve 5 miles or 3000 ft separation between non-participating aircraft, the moment you do not accept a request for not above 2000ft you become non-participating and hence a problem. As already asked why do you need to refuse this unless for terrain or awkwardness. As you argued about ATCO instructions on a previous thread how would you feel if a first cross country solo was allowed to depart up to any level and ended up in an airprox or worse, when a simple not above 2000ft would have kept everyone safe and moving. You queried how this request constitutes traffic info it doesn't because if one is not above 2000ft and the other at 3000ft they are not traffic. As stated before everyone avoids each other, everyone keeps moving towards where they want to be, what exactly is your problem with this? As for the, well what if I have an airprox with someone below 2000ft question, this negates your stance of we are all capable of seeing and avoiding so just let us get on with it and if you have seen it and the only way to avoid is to climb then either ask, if time, or act and tell us why, believe it or not we are trying to avoid collisions happening as much as you.