To be serious for a second, matching clothing in these kind of situations can be useful for children.
I visited Blackpool Zoo once, taking 4 young boys by myself. They were wearing matching tops.
Walking around was fun but good grief! It was like herding cats.
Turns out the matching tops was a godsend, I could keep an eye on them easily because I could spot them very quickly in a crowd and keep an eye on them even when run off in different directions to look at things. Blue with weird pattern in the corner of my eye? No problem.
TL;DR: Matching tops are excellent for keeping track of a group in a crowd. Whether that’s to find them or avoid them, as already pointed out 😉