I have a 1990 Civic 4-door 5-speed with those annoying automatic shoulder
harnesses which don't seem to be providing the restraint that the lap belts
and rear-seat shoulder harnesses provide. If I tug on them quickly they
don't lock in position, unlike the others.

The Honda dealer I consulted states that they're a differently-designed
mechanism from the lap and rear-seat shoulder harnesses and will work
properly in the event of an impact, but I don't believe it and am feeling
quite unsafe.

I've _never_ encounter such shoulder-harness behaviour on any other auto or
aircraft and feel that the dealer is wrong. Can anyone corroborate the
dealer's statement please, or suggest some sort of test to show that the
front shoulder harnesses will work properly?