Itís the prepackaged coffee filter things that appear to be the culprit here, as the buildup of pressure might cause a little boom or bang. Thereís been several reports of first and second degree burns from these coffee attacks, so we guess that the FAA just wants to ensure that flight attendants know what theyíre getting into when they brew a pot of coffee.
It sounds like that as long as the prepackaged coffee things are placed into the machines correctly itís kind of a no harm no foul situation. However, if they are stuck in there incorrectly thatís where the problem occurs. Just watch out if youíre hanging out by the coffee pot, and be hopeful that your flight crew holds down a weekend job at the local Starbucks.