I been reading this thread quite closely, good instructive and informative comments from both sides of the fence so to speak.
With regard to whether we (the ATC's) can see if you are off track, here in the Middle East we certainly can. The new kit we have is pretty good, we can see to within 0.1nm if we feel like it.
Having said that, I do see many aircraft sitting comfortably 1-2nm off track on a regular basis. I personally have no problem with it unless I'm RADAR vectoring, then it would be impossible for the pilot to offset anyway wouldn't it?
Having heard of many opposite direction near misses (and same direction come to think of it) coming out of the airspace to the east of us...I am more than happy to see the offset happening.
BTW willadvise...I haven't been in Oz for a few years now...are you guys now using the ICAO 15 degrees 15 miles now? I have always felt that 3.75nm is not really enough...if we are using radar, we need 5 (usually)so I can't see that 3.75 is safer.
BTW someone asked about lateral separation...it's 1nm between the POSSIBLE positions of two aircraft (that takes into account the xcross track errors and adds one for mum).
Keep the good gen coming, I feel it is of benefit to both sides especially with the possible implementation of RVSM in most places of the world.
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turn the plane! turn the plane!