I am a visitor from the Leica and Zeiss users club with no long-term experience with Swarovski binoculars. Of course, I would not doubt doubt at all Swarovski's assertion that their products are waterproof, but would doubt whether the seals of a specific pair after many years of use are still effective, and the gas is still there. This feeling echoes the experience I had with Trinovid BA model that was sent to Leica for service after many years of use (more than 10 years in this case). The service items included change of seals and gas-recharge. Accordingly, I would not doubt the watertightness of a relatively new pair of Swarovski binoculars, but would be careful if the pair is considerably older. Given that I heard excellent words about Swarovski's service, it is rather difficult to envisage a problem in ensuring that your binoculars are up to standards. Enjoy your canoeing in good health.
PS: Although that I am conservative whenever I canoe (calm, neck-deep, clear waters), I have found the floating strap assuring--so it is a good idea to acquire it. And yes, I have tipped over twice, but because the binoculars still remained around my neck, tipping was not an issue (except the children--watching me form the safety of the jetty--laughing at me for days).