I live in Whitehorse Yukon and have been accross the border into Alaska and back about 40 times in the last 4 years. The border guards up here never ask any questions and I travel on an Aussie passport. I'm a PR ( just applied for Citizenship ) and have always been in status. They never scan your passport up here. If I was out of Status and wanted to get back into Canada it would be so easy. I would fly into Juneau Alaska and then take the ferry to Skagway. I would then drive to the Yukon. The customs at Fraser BC are always asleep and don't ask many questions. I would just tell them I was on Holidays and wanted look around the Yukon for a few weeks. It's only a 2 hour drive from Skagway to Whitehorse. Then you can jump on a plane to Edmonton or Vancouver for about $350 each.
It makes sense. If you really think about it, Alaskans and Yukons are kinda thesame people. If not for the geo-political boundaries that Governments have set in place, they should be living as one. Also the population in that area is small. What is the point of wasting time and resources or even scanning passports? Someone living in Alaska might
genuinely have to be in Yukon for a while and then go back to Alaska without even worrying about Immigration and Customs.