No, reverse bias is the normal mode of operation for many semiconductors,
including the transistor collector-base junction, and rectifier diodes
which are reverse biased for most of the AC cycle. What's potentially
damaging to some semiconductors is reverse biasing at a voltage high
enough to cause breakdown. If done repeatedly to the emitter-base junction
(which is normally forward biased), it can result in reduced transistor
hfe. Of course, since substantial current flows when breakdown occurs,
there's also the possibility of complete destruction, e.g., melting of the
silicon, due to heating. Zener diodes are intentionally operated in this
mode, and the designer has to make sure they don't get sufficient current
to be damaged.
In contrast, forward overvoltage is difficult to achieve. Because of the
exponential I-V relationship of a forward biased diode junction, it takes
a great deal of current to raise the forward voltage much. That's why a
reverse connected shunt diode makes an effective limiter for negative
transients. (Negative transients forward bias it.) There is the
possibility that some junctions in the device to be protected will turn on
at or near the same voltage as the snubber diode, but they're likely to be
current limited in some way. If not, a hot carrier diode, with its lower
forward voltage, might be used.
The best approach is to use devices like ICs which are specifically
designed to survive in the automotive environment -- where another very
significant hazard to electronic components is potentially extreme
temperatures.