This is an interesting point. I am getting out of topic here, but most of my BB shells have drain holes in them. Some of the steel lugs actually have huge ornate holes in them. In addition, there were no nice sealed BBs in many of these older bikes, but somehow these survived a very long time that way (with contamination getting in). My Litespeed Tuscany also has a drain hole at the bottom of the BB shell - and since it is titanium, I am guessing that it is so that the BB doesn't sit in puddle of water. As a matter of fact there is a large hole in the plastic cable guide so that the BB shell hole is not covered by this plastic cable guide.
These sealed BBs are marvelous, especially for mountain bikes, but I am interested in the real purpose for the hole in the BB shell and why some shells have and others don't. I don't buy the explanation of a Supergo sales "expert", who once told me that it is for "ventilation". Can someone who really understands the issue and tradeoffs explain it?

Kaiser, I think that you have a great point. If there is a maintenance needed on a bike, without which there will be a short term damage (more than ordinary wear), it should be pointed out in and out of manual. Furthermore, Trek sold is the bike maker, not Shimano. Why should you be required to deal with subcontractors on fancy bike which should be still under warranty? Shimano then can tell you that the shell parts are from company XYZ from Korea, and you'll have to follow with them? They designed, manufactured and distributed the bike, they should make sure it works as a system with all it's components. I work for a company which manufactures complex systems using components from many sources, often several souces for the same component. We would never consider to suggest to a customer who has a problem with the sub-system to take a component out and deal with that manufacturer. That wouldn't get us far.