You can find all the operational manuals at
http://www.cic.gc.ca/ENGLISH/resources/manuals/index.asp
Go to Overseas Processing and look for "OP 10 - Permanent Residency Status Determination". At the bottom of page 13, it says:
The permanent resident card is not issued to permanent residents who apply for it outside Canada [R55]. Rather, permanent residents must submit their applications for a permanent resident card in Canada.
However, nothing prevents a permanent resident residing abroad from travelling to Canada to submit an application and providing a contact address in Canada where they can be reached in the event that further information or a personal interview is required. To be provided with their PR card, applicants must attend at the time and place specified in a notice within 180 days of receiving notification that the card is available [R58(3)].
So travel to Canada in order to apply for a PR card is still perfectly legal according to this and just like any other PR, this person has no travel restrictions during the processing time of their PR card so they can leave again if they wish. As long as they can come back in case they are asked to pick up the PR card in person. Which they probably will if they told immigration that they are living overseas.
