Happened with us in August. Interesting that they don't pick it up as you cross the land border, just when the boat roster is submitted in advance.
I can explain why this is....
When I lived in SE Michigan (Metro Detroit), it was very popular with the boating crowd to head by boat across the Detroit River or Lake St. Clair to popular Canadian destinations, such as Windsor or Belle River.
When you cross by boat, you normally pull into a dock. The first thing the dock attendant does is escort the owner or responsible party of the boat ONLY to the nearest customs phone, located on the dock. The others MUST stay on the boat and may not step off the boat for any reasons.
The owner picks up the phone receiver and is immediately connected to customs. He / She provides the MC (registration #) of the boat, boat's call name, his/her full name. The Customs person will type this information into their computer and literally, pull up every single time that boat has cleared Canadian customs.
ALONG WITH THIS LIST is the name of the typical people always on the boat. The customs agent will actually say, "Is Natalie with you today?" or "Are you traveling with the two dogs?" :shocked2:
If there are others onboard, the owner must provide their full names, date of birth, citizenship, why they are ON THE BOAT.
This database goes back for years! I know of one boat owner that drydocked his boat 1 year, did not visit Canada for 3 years and on the 5th year did a weekend trip to Belle River and they could pull his info up.
If you haven't driven across the border, you may not realize this, but at the custom's booths in your cars, your name is never typed into a database. I believe they do check license plates, but, I'm not sure. I really don't think so based on the conversations I have had going through customs in my vehicle.
Also, your boat is not as portable as a car. So, they have TIME to run details on the persons on board the vehicle and can usually track the boat down at the docks. For example, If you pull into a Windsor marina on Friday, they want to know where you and the boat will be your entire stay. If you are heading to Belle River from Windsor, you have to declare it. If you don't, well, we never tried to find out how funny Canada would think it was.
So, yep. It makes sense that they catch up to someone more quickly and commonly who is onboard a boat, rather than someone driving in with a car.