Just how easy is it to make a liquid bomb in flight?

Liquids on a plane! How much of a real threat is this? The Register has this analysis of just what would be necessary to make a liquid explosive on a plane. Our experts appear to be more expert in watching movies than in understanding chemistry. There are real threats out there, but so far they seem to be resoundingly ignored. Much appreciation to Dr. Doom, who also explores the problems of flying without liquids.