They not only do stuff like this. . .
they put together a temporary stage, and do it in public!
(note especially the old lady haircuts, which are EXACTLY like old lady haircuts in Canada.)
Ajummas play a funny role in Korean society. . . they're a much maligned group known for elbowing people to get empty subway seats and bawling out vendors in harpy voices for refusing to cut another bit off the haggled-price, but then, they can be hilarious and charming sometimes, too.
(Ajumma at her worst:)
(at 2:35 in this video, Halmoni -- the older, meaner version of ajumma, shows up and basically terrorizes everybody for the rest of the song)
However, sometimes Ajumma can just be wonderfully fun. Here's another story about a delightful encounter with the Korean Ajumma.