Kettle Sniper

A person who uses the hot water from a freshly boiled kettle leaving nothing behind for the person that actually boiled it.

Generally in an office or communal kitchen, where someone will go to make a tea or coffee, fill and turn on the kettle. During the 2-3minutes taken to boil the water, they may go to the toilet, answer the phone or otherwise get distracted. When they return to the kitchen the water ha been used and they have to refill and re-boil starting the time wasting cycle all over again.
Additional annoyance may occur when the first person has placed a Mug or Cafetiere on the side with ingredients inside ready for the water, but the second person has ignored this and continued without any regard for the first

Some Kettle Sniper stole my water when I was in the toilet.

I went to answer the phone and the Kettle Sniper struck.

I've tried twice to make Tea but I keep getting Kettle Sniped