Particularly since cut hair doesn't even contain DNA. Or at least that's what is claimed by random web sites if you ask a search engine. Never mind a full genomic analysis, even for forensic purposes it is claimed that you need hair with the follicle attached. Is that still true, or is that claim now out of date, I wonder.
It does seem like the state of the art differs from popular understanding. Not only is mitochondrial DNA straight forward (although not especially useful for forensics as it is maternal), but with specialized extraction it is still possible to recover nuclear DNA, just exceedingly painful to do so.