Is it possible to simulate multi developer scenario with RTC source control so that when I make code changes I can test accepting change sets for example. This is just so I can test a multi developer environment but using just one user.
I’ve tried creating multiple Eclipse workspaces, and loading the same project area into each Eclipse workspace. Using this method I am unable to accept change sets as RTC source control will just ask me to resync my workspace once I make a change in work Eclipse workspace:

It seems the only method of accepting incoming changes is to
1. Right click on the stream from within ‘Pending CHanges’ view
2. Select load
3. Select following option :

Make sure you use the Stream (ie make sure you don’t deliver directly to another repo workspace simulating another user)
(Note: this is entirely different in ClearCase, where the “out of sync” can happen between the configuration of an UCM view and the one of a Stream after a rebase)
If you create different repo workspace (loaded in different Eclipse workspace), this can cause some confusion when used within the same Eclipse instance.
As said in this thread
That “confusion” is explained in the same thread:
Check out point 7 and 10 of “Good practices and key workflows for Rational Team Concert Source Control users“.
Note: the article “Loading Content from a Jazz Source Control Repository in Rational Team Concert 2.0” (also valid for RTC3.0) mentions in the section “Reloading Out-of-sync Shared Folders” a similar advice than the one given by the OP:
Also the thread “How to handle project out of sync ” provides an interesting illustration of that mechanism (even though it isn’t exactly your situation).