“There’s this game called sardines, how it is is the hider is the person that everyone is trying to find, so it’s not like hide and seek, and so once you find the hider, you have to hide with them in the same spot. As people keep finding you, you keep getting larger in your group. So as the first hider, you have to find a spot that’s really good, so that people can’t find you, but then also good enough that if people start clumping in, they won’t be seen.”

While listening to my informant tell me how “sardines” is played, I began to think of how similar it is to hide-and-seek, despite her insistence it is not. I have also heard of this folk game, and it must be quite common across different communities in California, at least, if not the rest of America.
Huffington Post groups both hide-and-seek and sardines together as the same kind of hiding game, in the following article: https://www.huffingtonpost.co.uk/2016/08/01/fun-traditional-games-parents-played-when-children_n_7553124.html.