“A seasoned scientist can probably accurately judge whether the change is a mutation or a cut.”
How?
What is the basis of that statement?
Just supposition. I suppose when the change involves a series of nucleotides, the longer the series the less likely that it happened randomly.
A scientist involved in gene splicing has seen small random mutations “under the microscope” (the sequencing data), and has also seen larger engineered insertions or swap-outs in samples he or his colleagues have tinkered with. I expect with experience he can tell the difference, based largely on length and likelyhood.