Thanks, again, to all who commented. I'm no cowboy, but certainly accept the advice of seasoned folks that safety trumps a nice clean mower deck. I'll attribute the absence of replies to my original question (will it hurt the mower?) to a not-so subtle opinion that I was asking the wrong question.
Although I've since added the "safety" back-up I spoke about (chains suspended from a reinforced second rafter and hooked to the tractor), I'm not sure I can overcome the mental phobia your collective posts have created! Looks like it's back to car ramps.
Logically, the deck has lasted 15+ years and is in good shape so even if I don't clean it, it's probably going to outlive the useful life of the tractor. I try to mow when the grass is dry so there's not too much build-up anyway. Never gets clogged like ovrszd experiences in NW MO. Still, it's like painting behind the refrigerator - even if I'm the only one who knows, and it serves no useful function, it is just satisfying to do.
Logically, the deck has lasted 15+ years and is in good shape so even if I don't clean it, it's probably going to outlive the useful life of the tractor. I try to mow when the grass is dry so there's not too much build-up anyway. Never gets clogged like ovrszd experiences in NW MO. Still, it's like painting behind the refrigerator - even if I'm the only one who knows, and it serves no useful function, it is just satisfying to do.