Same story as Ian.
Because there is no advance mechanism with bob weights hammering ( well tapping any way )on the taper as you get with the auto advance models there is little to cause the pinion to walk on the tapper
I carry a pinion puller inmy kit as well and like Ian have never used it roadside.
I have been known to cheat on occasions on the side of the road and alter the points gap when I suspected the mag on some one elses bike was off time a bit.
The only time I get s slip is tightening the pinion bolt but a LIGHT tap with a lead or leather mallet will usually lock the taper before you tighten the bolt
Note the use of the word LIGHT amd it has to be a dead blow, rubber mallets just don't do the job