I think that it is easier to make noise when thrown hard, easier to be silent when thrown soft, but possible to be either in both cases---it just take more focus and effort to be silent with a hard throw and loud with a soft one. Like practicing variations on technique, I think it is good to try them all. I do not find the demo uke falling hard to be distracting, nor do I find those around me falling hard to be distracting, but perhaps I am more able to ignore noise from working in ERs
My first sensei could do a silent breakfall, a goal I have not yet reached.
I have had others twice my size thrown on top of me, even on fairly deserted mats, so I tend to slap hard when near others as a self defense, be aware I'm down here kind of thing.