anon:
Even with the minority of carriers that provide that detail, it is not complete. If the caller blocked their phone #, in the majority of times the number will not appear on the itemized statement. Have you never seen an incoming call on your bill that lacked a number? I don’t think you – or anyone – can make such a claim. (And this is in addition to the ingenuity of the youth I alluded to previously, that will enable them to take counter measures to even normal blocking and itemization.)