I've had all kinds of water related failures - but not due to "light heads" so much. I've had Dinotte battery fail due to moisture after being a really bad thunder shower. But yes, on the other hand - the lights have continued to work.

In the past - I've had Cat eye front and rear lights fail as well Vista lights and some others.

But no - I have not had a MS or Dinottee light head fail yet. (due to moisture)

I had a MS tail light fail after being in long rain ride.

It is hardly "BS" to tell people flash lights are more water proof than other types of lights. It's common sense - and the truth.......