As one who boards in zone 1 and yet has traveled with children under 2 I have always thought Air Canada should have done like they did before zone boarding was introduced is allow those with young children to preboard.

It is against policy now but I think the policy is wrong.

Generally those with with young children are further back on the plane. Let them get on and give them an opportunity to settle in before the hordes join them at the back. Those in zone 1 and 2 are usually nearer front so those with kids are settling in at back from 1 and 2 board and then as 3-5 board then the young families are settled and no longer an issue.

Now what I often see is families trying to get settled while those in zone 3 are trying to get into seats etc before they are situated.

As as noted UA does it the right way and I have yet to see an issue when I board in zone 1 that those little ones got on ahead of me.