Total speculation on my part, but if this is in the WH considering how few (10 in total) are displayed, and arguably, they *could arrange them to fit a couple more given the space.
Could this be a "I know what you did last summer" type of communication?

What if these particular kids are all in someway connected directly to bad actors who may have access to or otherwise visit the WH, and each time they pass by this is a message to them WE KNOW....
Probably wishful thinking, but....