Great question — answering as the UphillTech team:
Two preliminary points based on the comments This answer assumes that ETIAS is not in place at time of travel. ETIAS. Once ETIAS is in place, this is likely to be wrong This answer boils down to "keep the group together if any possible". Chances are that that can be done with either passport, but using the Canadian one will guarantee it. At this time (before ETIAS) the traveler can use either one, and using the EU passport is often the best choice. However, this is group travel with minors, so there are other things to consider. I assume that there are one or more supervising adults with the group who are "responsible" for getting the kids to the final destination. Using the Canadian...
Full answer by Hilmar: https://travel.stackexchange.com/a/204001 (CC BY-SA 4.0).
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