We generally like to anchor in the bay of Milford Haven on the south east end of St. Joseph Island when returning to Michigan the North Channel. This year Canada Customs/Immigration is checking boats in the area for proper entry registration numbers. We were told that a police boat with four officers comes through the anchorage every evening at about 8 PM.
Sure enough, they were there at 8 PM in the evening. They were very friendly and told me that the fine for illegal entry into Canada has been increased this year from $100 to $1,000. They also confirmed that the customs phone up the little river in Milford Haven is for snowmobilers only, not boaters. If your boat is at anchor in Canada, you are considered to be on Canadian soil.