Tundra_Man 

I watched part of IM Wisconsin last September. It was a pretty cool experience. I do triathlons myself, albeit so far just shorter length races.

As near as I can tell (and from what I've experienced) every level of triathlon induces lots of pain. A sprint tri may not last near as long as an IM, but due to the shorter length people pace themselves significantly faster. I'm not going to say the two are equivilent by any means, but both are quite effective at inflicting pain.

Some courses lend themselves better to TT bikes, others lend themselves better to road bikes. However, many athletes own only one high-end bike for racing, and have spent many hours training and dialing in that one bike. Most athletes will compete in more than just one race during their lifetime. I know on race day I'm bringing out my TT bike regardless of the course, because that's the bike on which I've trained myself to go fast.

Ideally it would be nice to close the race course, but that would take a lot of doing to attempt to shut down a 112 mile stretch of road for 8 hours. Shutting down 3 miles of road (5k distance) for 45 minutes is much easier and is why you see that more often. That being said, I've never done a tri or a running race of any distance that had the course shut down to traffic. At best, as you noted, they have volunteers trying to direct traffic.

The person you saw receiving outside assistance was definitely cheating. Even accepting water from a non-volunteer would be considered cheating in most races. Myself, it would always eat a me knowing that I broke the rules, but some people have the ability to live their life "scruple light". Heck I have a hard time even watching draft-legal tris on TV, just because to me it seems like in some way their cheating even though in those races it is allowed.