Certain courts and agencies codify this tradition as an administrative rule (usually expressed in terms requiring filing of “original” or “executed” papers). Some are more liberal than others as to what can constitute an “original.” With the advent of faxes et al., it’s my impression some sectors of officialdom are getting more flexible (e.g., accept a photocopy or fax, period, or accept a photocopy on an interim basis as long as the “real” execution page is swapped in later). Certain clerks have been known affirmatively to refuse copied filings, going so far as to lick their thumb and swipe a black signature to see if it smears (and thus is pen ink) – signing in blue averts all that.