Fishjunkie, although you may have received assistance with a BoatUS membership in Canada in the past, the future will not afford you the same great results. It seems that the area BoatUS sub-contractor has been illegally crossing the border to lend assistance to Canadians and this practice has been brought to the attention of the RCMP as well as the Canada Border Protection Agency.
An American service provider can not legally provide service inside the Canadian border. They can only lend assistance if the vessel is being returned to The US. Although BoatUs will still provide coverage via reimbursement, they only cover $125.00 per hour (as outlined in their own terms) which means...
Your call will be referred to a Canadian assistance provider (Canadian Coastal Services being the only company serving Lake Erie, The Detroit River and Lake St. Clair). You will have to pay the bill in its entirety @ $240 per hour then wait to be reimbursed $125 per hour from BoatUS.
Alternatively, you could pay the annual membership to your Canadian provider that will be providing your service and enjoy the service free of charge. You unfortunately won't get a magazine out of the deal but with the $9 you save in dues you could hit the news stand a couple times.
All of these facts can be confirmed with a simple call to Canada Customs asking them to explain how these acts violate Canada's cabotage laws. Another to BoatUS asking them to confirm they have a contractor in the area that can legally cross the border and work in Canadian Waters without violating these laws.
Which every route you go, have a safe boating season!