>>280639761
The woman's sash has the word "こども" or "child" on it. Presumably, it says こども会 in full. Also, Furinkan has a very silly note here, but I'll post it anyway:

"The event the black cats are asked to participate in is a "stamp rally" (スタンプラリー). This is a game where people travel around (sometimes from train station to train station or tourist destinations within a city) collecting stamps. The first person to fill their book and arrive at the finish line is declared the winner."

スタンプラリー (sutanpuraree) being a loanword from the English term.