The Canadian Department of Foreign Affairs and International Trade strongly recommends all consent letters be stamped or sealed by a commissioner for oaths, notary public or a lawyer so the validity of the letter will not be questioned.
Notary Public Signing: To be of full effect, this document should be sworn and signed before a Notary Public or a Commissioner for Oaths. Do bring government issued identification and the child's birth certificate. DO NOT sign this consent form before meeting with the Notary Public or Commissioner for Oaths.
Witness Signing: It is possible that signing before a Witness instead of a Notary Public will be adequate. However, we recommend you check the current policy of your airlines and/or the countries you are traveling to before taking this approach.
Note: If there is a custody order or death certificate, the original or a certified true copy should travel with the child.