I think the last statement in that quote summs it up. An airbag system is referred to as a suplemental restraint system - meaning that it should be used in addition to a seat belt. SRS sytems do vary by manufacturer, but it is very common to have a weight sensing device on the passenger side only. This helps determine if anyone is present, if a child is present, or if an adult is present - and controls the airbag deployment within the programmed parameters. Driver's side airbags should deploy regardless of whether or not the seat belt is buckled.
"Of course, I could be completely wrong". (Dennis Miller)
"Of course, I could be completely wrong". (Dennis Miller)