A consent letter demonstrates that a child has permission to travel outside Canada from every parent or guardian who is not accompanying them on the trip. There is no Canadian legal requirement for children to carry a consent letter.If children are not travelling with both their parents, (ie: if they are travelling alone, or with another adult), this form can be used to give permission. Parental consent documentation for travel to Canada and Mexico. Border Crossing Consent Letter- Only applies to those 18 and under traveling from outside of Canada. Upon arriving in The Islands of The Bahamas, everyone must fill out and sign an immigration form, keeping a portion of the card in hand until departing. I was asked to present the consent form at immigration when I was returning home from the Bahamas with my grandparents. I was 15 at the time.