Don right it won't hurt anything more than usual. Can be any worst then when I shift it in fist gear... feel like the dog ring will come out of of these days. Once you pass the second gear, the slip are so close that both gear are almost turning at the same speed. I never downshift without clutch... this is where you will damage the dog ring...Not completely true. There is excess wear on your gearbox, you just may not necessarily notice it, for a while. There isn't really an advantage to not using the clutch, unless you're running a quarter mile and 1/10s of seconds count.
I use my clutch, preload the shifter, only give about 1/2 pull from 2nd up, and I can hardly feel the transmission shift. I'm usually shifting around 7K and will jump that up to 10-11K when riding agressively.
From all my year of experience in racing, most of it I was in charge of the gearbox. There's 2 way of really damaging a gearbox. 1- getting lasy upshifting or not bliping on downshift. (race car gearbox don't have synchro mesh, they have dog ring just like bike... use the clutch just for take off)
Worst gearbox ever: Porsche 911 GT3! Not done right, I've seen a gearbox going junk in 3-4 laps at Daytona one year...