I don't think anybody would be thinking of offsets below at least FL100 and my personal suggestion, FL200.
However, the smart folks at ICAO don't sit up night after night watching opposite direction traffic passing PRECISELY head-on time after time after time after time after time after time.......you get the message.
All the talk about pilot tolerances, equipment tolerances, the need to recalculate safety heights for the offset route, the need to recalculate latsep points fot ATC sounds just great. It ignores one thing, GPS equiped a/c today ARE EXACTLY ON TRACK!!! And they WILL hit head-on if someone makes a mistake.
The boffins, to use that American expression, need to get out more. So do the ICAO and IFALPA folks who sit around pontificating while the rest of the world wonders.
For mine, an official 1nm offset above FLxxx can't come soon enough!
G'day