I wonder whether it is worth answering, since your purpose is to insult rather than consider the merits or otherwise of what are real problems.
Two problems observed in real world marshalling are indeed (first) misrecognised or misheard numbers resulting in duplicate numbers apparently passing the same marshal at different times - And another not passing at all - if you have not seen it you have not done enough of it , and more importantly I recollect formed part of recent evidence and ( b) lost numbers or tags.
Wynn actually tried at one of the first waltzes the carrying of a bangle of tokens, problem is runners were losing them ( both individual and entire bands) rendering it impractical.
Wristbands are indeed practical fell running.
SHRA have on occasion been using hospital style wrist bands which have to be cut off ( avoiding the loss situation) - solving one of the problems - but it does not solve the problem of tring to do what FRA claim to do, which is be able to track and identify who is missing before the end of a race which needs automation to make it easy and fast and practical.
So in order ( a) to have a second check on misreads and ( b) allow FRA to achieve more of a reality to the myth of tracking and (c) to do it without spending a fortune, bar code reading is provable technology that may be worth a test from numbers produced on an ordinary printer.
Good mobile phones can do the read, as can a very cheap device.
The reality is you have operated rules which have been impractical for years - it took this event to highlight it, and even now some of you have heads in the sand.
I keep asking FRA to publish UKA evidence for people to see the reality of what they face. It needs some fresh ideas.