We have a 40' MH and never had a problem. I think there's a collapsible orange cone someplace in one of the compartments that the wife wanted to take with us, but I've never gone looking for it.
For the road I prefer the orange triangle reflectors. I think they show up better and they take up less room.
Bill
Nodwell RN110 out moose hunting. 4-53 Detroit, Clark 5 spd, 40" wide tracks, 10:00x20 tires, 16,000# capacity, 22,000# weight. You know the mud is getting deep when it's coming in the doors.