It starts like this: one Wednesday afternoon apropos of nothing in particular, the centre vending machine of the bank of three in the shopping mall's bus terminal starts beeping. The beeps are loud and frequent, one every half a second, and a red light nobody noticed before flashes in time.
This is the vending machine people use the most. There are two reasons for this. For one, the device has the greatest assortment of food items which could, in a desperate moment between bus transfers, become a makeshift meal. For another, it's the only machine in the terminal which can ingest paper bills and spit out change, something both the transit workers in the ticket booths and the lady at the lottery kiosk upstairs both refuse to do.
People hurry up to the vending machine, fivers in hand, and groan when they realise the beeping they heard is coming from it.
A man in a suit and overcoat shrugs and pushes his money inside anyhow. The machine rewards him with a prompt to select some junk food from its innards. He leaves with a chocolate bar and a handful of change.
After the man's example, there is a steady stream of people using the machine. Nearly all of them arrive as a previous customer is showing up. If there's a gap, the teenagers loitering at the doors are more than happy to inform the next person, though they're not very polite about it.
"You should have time to get some candy before the thing explodes," they say. Or, "It does that when it sees a fat person's gonna buy more candy. Take the hint, bitch!"
Eventually, the last bus for the night leaves. The transit workers kick out the teenagers and lock up. They finish counting the tills and go home. The last one out turns off most of the lights. As she passes the bank of vending machines, she stops, peers, checks the gap between the wall and the backs of the machines, and gets on her hands and knees in front the centre one, which is still beeping and flashing. Her arm is just long enough to reach under and behind the machine to unplug it. She gets up and goes to the ticket booth, where she writes a note to the morning shift.
In an attack ship hidden behind the moon, the Zorguan intelligence commander slams five tentacles into the control panel. "Who planted that observer equipment and didn't install an independent power supply? We need at least one planet rotation to get complete data."
"Never mind that," says the second in command, "According to the advance reports, that sound and that coloured light mean danger in their culture. But hundreds of people walked by and ignored it, and tens more used the machine."
"They're either very brave or very stupid," chimes in the admiral, waggling a tentacle. "Probably both. I'm calling it. Don't worry about completing the intelligence collection cycle. The only thing to do with a race like that is dematerialise them from orbit."