Today at the local tournament I noticed this. It was my turn - my opponents clock was running.
It turned out to be this way. My opponent had pulled the time control of his neighbor, accidently. We was playing two on each table, (sitting four people on each table in a room). Some time had gone while our dear neighbor had lost time on the clock. Naturally we did like this, pulling his clock. The question was this. How much extra time would our neighbor get, the one whos clock had been pulled.
I called the judge and we tried to correct the misstake (very improvised).
We did not know how long it had been this way. What to do?