I've been,"banging" gears on bikes since '69, I rarely use the clutch up or down shifting, just in rare cases, like to bring it back on the pipe or some hills. Been in a million MX,SX, HS, Enduro's, never popped a gear or a trans. I do change the gear oil a lot, (@100 miles or each race)
But, there's always a chance you can do damage, with or without the clutch
Joe
2001 KDX 200
2000 ATK125
2-TTR 125 Boy"A"'s and "B"'s
Falling is like a reality check, it lets you know your not as fast as you thought!! :)