Well, weight have something do with it, the hardness of the wheel, and other factors.
most industrial caster wheels are designed for high load and easy rolling on smooth surface, therefore they are hard as hell...
street skateboards also have small and very hard wheels (and short wheelbase), so they also lock up and skid with small rocks. (done it many times
but big soft longboard wheels just flicks rocks out of the way,
rollerblade wheels and Razor scooter wheels just don't have this problem, narrow profile.
you just dont see kids on Razor scooters fall by skidding to a stop from a pebble
my kid brother had a knowped (motorless goped) with semi-hard solid rubber tires, fat profile, not that bad also.
I never really seen gas goped with the same solid rubber tires skid to a stop from a pebble.
yes these egret wheels are smaller, but I don't see the pebble lockup thing happening.
even if it manages to happen, most likely at lower speed, your back foot would naturally plant forward, thus unweighting the scooter and pop over any pebbles.
Rgarding riding inline skates its quite different from riding a scooter...
the big problem like i said is elevated cracks, but with a light scooter you can plant-hop over them fairly easily ..
with this ride its probably not suited for anyone over 180lb,
the harsher the shock the more u weight,
heavier riders are probably better off with at least a 8" or 10" air tire,
or those big xootr wheels but the ride is also very harsh on those.