So we have a better safer system because we provide a DTI to IFR in G. But to do that, the aircraft have to be on an ATC frequency. This makes our "area" also an ATC frequency. Canada don't do this, because G is blanket 126.7. ATC is provided in the other various category airpaces on other frequencies, I presume. Airspace category boundaries are shown from what I can gather, so Canada does have ATC boundaries marked on their charts. They just don't have area boundaries marked as there are none. If our various area frequencies are also used as ATC frequencies due to our better safer system, I think it is legitimate that their boundaries are depicted on the relevant charts, just like other ATC areas are.