I certainly take your point that there could be some challenges for Canadians who may not have lived in Canada for some time, but every elector who lives and votes in Canada has to provide either one piece of ID with their address or two pieces of ID with at least one that shows their address, or they must have someone vouch for them who must establish their address.
There seems to be a bit of inconsistency. I guess if you can't establish proof of your last place of residence, what is there to say there aren't electors who are, for example, randomly selecting ridings, strategically selecting ridings or selecting ridings for any number of reasons? That would seem to me to be a gap. There needs to be some sort of verification, because by law, it's not as if a Canadian living abroad can vote in any riding. By law, they can only vote in the riding they last had residence in.