Yep, just as I thought. I bought bagels from both St-Viateur and Fairmount. I tasted them, unidentified from which shop. It's impossible to tell them apart!
Here's my therory: It's like that TWIX chocolate bar commercial. Two brothers got into a quarrel and decided to open their own bagel shop. They are equally convinced that theirs are better. While in fact, it's probably the same recipe.