Self-clear area

I spent a while failing to interpret this sign. It seemed to be saying that if you didn't clear your tray... then you'd get ketchup poured on your wrist?

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Printed sign reading 'this is a self-clear area; thank you' beneath a red illuminated icon of a hand onto whose wrist a bottle drips.

It turns out there's a baby bottle warming station on the other side of the bins.

(It is possible they my brain is struggling from a lack of sleep.)