Witness incompetence rules that place arbitrary limits on an accused's right to introduce relevant exculpatory evidence are unconstitutional.

United States v. Robinson, 482 F.3d 244, 246-247 (3d Cir. 2007) (upholding trial court's ruling which allowed the testimony of a county narcotics task force officer about the admission of several buyers regarding their....The federal constitutional guarantee of due process may limit the government's right to introduce unreliable hearsay evidence against a defendant in a criminal trial.

17 U.S.C. § 410(c) (A sealed certificate of copyright registration is prima facie evidence of the facts stated in it.).Federal Rule of Evidence of 902(10) and comparable State rules provide that any signature, document, or other matter is self-authenticating -- i.e., requires no further evidence of authenticity to be admissible in evidence -- if an applicable statute provides that the signature, document, or other matter is presumptively authentic or if an applicable statute provides that the signature, document, or other matter is prima facie evidence of its own authenticity.

Cf. Bemis v. Edwards, 45 F.3d 1369, 1372 (9th Cir. 1995) (upholding trial court's exclusion of neighbor's statements on the 911 tapes because it was hearsay as (1) "[neighbor] was not a testifying witness;" and (2)....A prior inconsistent statement of a witness is admissible, not only to impeach the witness, but also as substantive evidence -- to prove the truth of the matter previously asserted by the witness -- only if the prior consistent statement was made in another proceeding.