turn off the water valve on the washer

clean the house

turn off the water main into the house.

pack way too much stuff.

Announce their trip and departure on social media (don't do this).

Forget to tie their shoelaces

Empty the refrigerator.

Stop mail/newspaper and other deliveries.

Ensure security alarms and night lights are working properly.

Forget to do all the above-except tying shoelaces ;-)

Go to the bathroom.

tj