Nice summary of the History Of The World As It Applies To Stopping Your Tandem! Thanks.

Good to get the bike shop perspective, that often helps in the decision-making process for an individual rider.

A few points:
1. I'm not so sure how convincing the "because they were designed for road" argument is for cantilevers. I find cantis harder to adjust than V-brakes - I can never get the pads in the right place in the former (individual user, not bike shop, but then I do most of my own maintenance, so that's what's relevant). I'm pretty sure suspension seat posts weren't designed for use on the road but my wife thinks it's the best tandem add-on ever....
2. haven't found in the past that pad wear is a problem on any given ride, but over time I do note that even my MB V-brakes wear out quicker than the cantis they replaced. (that is, I don't think it's a 'danger' - not like they're suddenly going to go through 2mm on a descent - just require more frequent replacement)
3. I get all the technical descriptions of the incompatibility between road levers and v-brakes, I'm just pointing out that I have not experienced any of the hypothetical problems - I find them easy to use with a very small amount of travel, they are neither mushy nor grabby. As far as I can tell they work just like the set up I have on my road bike (with standard road brakes)
4. someone asked if I've tried to remove my wheel - yes, I undid the QR and popped it out, after undoing the 'noodle'. I'm guessing that the TravelAgent might make that a bit harder, but I can pop the TA out fairly easily too, so I doubt it.