Let me backtrack. You said you agree with The Insulator in your Post on 7/10/00. BUT, what you said you did in your Follow-up to me on 7/11/00, you didn't quite 'agree' with The Insulator. On 7/11/00, you said you put down heavy plastic, wrapped the pipes, and shut off your vents. Did you add the crawlspace to the HVAC system? In other words, are you heating and cooling it?
This is what 'troubles' me with The Insulator's response. In SE PA, we DON'T seal off the crawlspaces. A vent is installed for every 200 sq. ft. of space. IN ADDITION, we insulate the pipes and the ducts. We DON'T add the space to the HVAC system nor do we install/recommend dehumidifiers. The vents are only 9" x 11" and are usually at ground level. No fans are installed either. SOME crawlspaces get wet especially if they're poured concrete. IF they get water in them, for whatever reason, no matter if it's just a little, the evaporated moisture has to go somewhere. If the space is sealed, it rises up and gets absorbed by the flooring above OR it makes its way through the floor and into the living space. This can raise a health issue. Some people with certain allergies have trouble with mold and mildew.
For what it's worth, I'm indifferent to what measures are taken to reduce/eliminate moisture/water in a crawlspace, so don't misunderstand me. I don't think ANY solution for this problem is a blanket solution. Maybe crawlspaces can be sealed in Minnesota or Washington or wherever. But in my neck of the woods, it's not generally done. (I'm sure there are situations where they are sealed but I haven't looked at them.) And I'm sure that the measure you took to 'solve your problem' work as you say but the other issues of 'trapped moisture' remain (and be OK with you and your household.) That's all. That's where I'm coming from. I can't say it enough. You, The Insulator, and anyone else has my blessing on this. It just doesn't agree w/me that easily.