this just happened to me for the first time
i took items of a glitchy khajiit chest near solitude's entrance and i was overweight so i dropped a elven battleaxe
a guard saw me doing it and he said that i shouldnt drop weapons on the floor because someone could get hurt, and if he saw me doing it again that someone would be me
Ouch!

They do that all the time to me. I guard'll dash up to me, & I'm afraid they've caught me stealing, but nope. They hand me a dagger I threw in the floor, & scold me for leaving weapons lying about where children could step on them. Or they tell me littering is a crime.

Once in a blue moon they will say don't leave weapons laying around like that someone can get hurt. Once I dropped a piece of armor next to the Markath staples and the owner ran up and asked me if he could have it

WHOA really???? i didnt knew npc's could interact with u ( us the players ) like that..interesting in depth..

I've never had an NPC pick up anything I've dropped or even comment on it. Not sure what triggers it.

They definitely aren't interested in Thalmor robes though.

i was overcomberd and i drop a dagger the a-hole run to my like i steal something

I once dropped a very nice dwarven sword which I had crafted myself in front of a guard in Whiterun. He told me "don't leave your trash lying around here". Kind of hurt my feelings.

ikr? he called it trash and u put ur heart and soul on that sword
if it was me i would pick on it and sell it
but what do guards know? everything that falls down to the ground (unless its a sweetroll) is trash to them.