The Canadian system is a little weird. First you get your Orange badge. That is qualified rad-worker. An Orange badge must be supervised by a Green badge. After six months or so, an Orange badge worker may be trained as a Yellow badge worker. Yellow badge is self-monitor qualified. Also, two independent Yellow badges surveying an item can free release it.
Green badges are the equivalent to an RP Tech. Most foremen and above are Green badged. The Green Man who is actually doing the RP coverage is separate from the foreman who is supervising the work. Both get paid as foremen for that shift. However, some Green Men have been shifted back to Yellow if they don't actually do the RP type work for a significant time. This is because it is too hard to verify the training is up to date for so many people who don't actually do the work. Another flaw in this system is that Green Men totally ignore all Yellow badged workers. Self monitors in such an environment are simply allowed to work without Green supervision (job coverage) regardless of where they are working or what they are doing.
Having worked in both Canada and the US, and having observed self-monitoring individuals in both, I can say pretty confidently that it just doesn't work. Not withstanding licensing requirements to have qualified technicians doing the surveys and job monitoring, it just takes far too much to keep so many people trained at the task.
It also takes a lot longer to do a job if you have to stop, put down your tools, take readings and smears, draw air samples, write up the results, put up the necessary postings, then go back to the tools.
While one RP can cover the work of several deconners at a time, having each deconner survey his own work will take a lot more man hours, not to mention that people tend to have a lot of faith in their own work and tend not to second guess themselves very much. Being pretty sure that you just cleaned a floor will tend to make you not go back and smear it a second or third time to catch the spots you may have missed. Besides, the spots you missed cleaning will be the same spots you miss smearing anyway.
Additionally, the RP part of the job always ends up being secondary to the task at hand. I very clearly remember watching self-monitor qualified operators moving about in High Radiation Areas with meters slung over their shoulders and not looking at them once. (Kind of hard to do when the meter is behind your back and you are reading a procedure while looking for the valves you have to turn.) Every one of them had the required meter, but no use for the thing other than as an admission ticket to an HRA.
There is a reason why lifeguards are outside the pool.