They might stand in line at the bank for another service, like to open an account or replace a lost debit card. Someone at the post office might stand in line to buy a book of stamps when the stamp-dispenser machine isn’t working. Or to mail a package instead of a letter.
In short, people could stand in one line for multiple reasons.
I’ve been a Catholic since 2000. Until reading CAF, it didn’t occur to me that a priest might make a grand statement by refusing to bless a child. It probably doesn’t occur to a lot of other Catholics, either. I’ve simply never met a priest who took issue with it.
What possible harm could come from a quick blessing for a small child? Getting this irritated about it seems petty and contrary to Catholic charity.