I have used a one rein stop on a horse who started to bolt while in the canter, along with a lot of other instances, and unless the horse is in a gallop, if you do it correctly and are calm and don't yank the horse's head around, he shouldn't trip.
I will use a one rein stop as a last resort or if I feel fearful. Bending the horse's head causes the horse to disengage his HQ's which takes all his power away. A horse can't run away from you with his nose at your toe ;) DO NOT pull straight back, that will only give him something to brace against (plus it makes horse's dull). If you do use a one rein stop, do it smoothly, don't yank him.
What I usually do if horses get impulsive is put them on a circle and ask them to bend their ribs to release the tension. Circles help impulsive horses calm down, straight lines help lazy horses become more motivated. Consistency vs. variety. The more impulsive the horse is, the smaller the circle. I really look for a horse to start sneezing, that's their way of telling me they are breathing better and releasing the tension in their rib cage.