If they are a genuine prophet, they will be correct, always.
IIRC the penalty for false prophets was pretty severe.
“Beware of false prophets, who come to you in sheep’s clothing but inwardly are ravenous wolves. You will know them by their fruits. Are grapes gathered from thorns, or figs from thistles?”
If you aren’t 100 percent right, every time, all the time, you are a false prophet and deserve the deepest, most painful place in hell.
There is no room for error.
“There is no room for error.”
My favorite false prediction excuse:
“Well, we moved into another timeline.”
;-)