DEAR MISS MANNERS: If you have a robot vacuum cleaner that runs through your house regularly, and it begins its scheduled run while you have casual company over, is it impolite to let it continue, or should the job be canceled? Does it matter if it is currently running in another room, where you can hear it but it is not underfoot?
GENTLE READER: Intelligent appliances are unavoidable, as are, perhaps, the crude attempts to anthropomorphize them by making them surly. It is only a matter of time before your vacuum cleaner orders you out of the way with a sarcastic quip.
Before that happens, Miss Manners wishes to remind everyone that your electronic devices are not your children. Etiquette highlights the distinction by reversing the now-ignored dictum about children: Appliances may be heard, but should not be seen. The robot vacuum cleaner can therefore be left to its own devices if it can be trusted not to make an appearance in the living room. Miss Manners says this in anticipation of the inevitable invention of the washing machine that wanders the house, absent-mindedly looking for discarded socks.
The rule must, however, be adapted to preserve homeowner and guest comfort: for example, turning off the dishwasher that drowns out dinner conversation, but leaving on the space heater that, the boiler having failed, is staving off frostbite.