Its a legitimate concern especially for the future and for builders of DIYs and Commercial Fixtures....
I myself have a few fixtures running north of 12 months of constant operation...But my grow rooms are humid and do expose the LES to moisture, thats a legit concern.
Lenses are not going to stop humidity sorry, that's not a solution at all....
They ask the tough questions, but the newbs want to AdHom it....Just because it hasn't happened to you in your multiple month grow, Doesn't mean it can't happen....
Don't shut the conversation down and devolve into the shitheads....So what if he whacks off to DE, it still was a legitimate question....That I really only see SDS having tackled in any sort of realm on these forums, at least recently.....Maybe that should be a starting point....