Seems very likely, even if there are no concrete examples of that happening.
You say "only be used to telepathically knock people unconscious or make your attacks stronger" but apparently Haki is capable of applying actual pressure on objects too.
When Shanks boars the Mobydick you see that many members of the crew almost faint even if he is still kinda restraining himself. But more importantly ou can also notice that Conqueror Haki applies physical pressure on inanimate nearby objects, causing actual damage to a ship that had traveled in the Grand Line for years and therefore is probably build to be more resistant than average.
It is true that somehow a tired Law managed to withstand Fujitora tremendous gravity powers, but I doubt your "average Joe" could do the same and withstand Yonko level of Haki pressure. I expect that a random passerby could and would be crushed if the Haki user intent was to cause damage.
To put that into context, here are some feats of Conqueror Haki clashing (notice: do not confuse Armament Haki infusion and Conqueror Infusion - the second one is the one with the black lighting effect).
Remember Kaido henchmen fearing that he would simply destroy the whole fortress (and the whole island) if his fight with Big Mom would go on for too much.
I totally expect that it would be reasonable that such force could crush an untrained background character to death.
Anyway it is worth noticing that most of the extreme example of Haki "explosions" were caused by two users clashing. Yet, Shanks example above seems to indicate that an extremely skilled user could at least cause a serious amount of physical pain on a weak, untrained person.