I was doing the clock at a (televised) D-I game last week when, partway through the first half, I realized that the Precision Timing system wasn't working. No big deal, before a shooting foul, I turned the system off and turned it back on - not realizing that 3 seconds would run off the clock.
As soon as I realized what happened, I hit the horn and called over the R. I calmly explained what happened and the time to which the clock should be reset. When I asked if I could reset the clock, he looked at me like I had two heads and said to just not start the clock for 3 seconds after the FT.
I don't even let the timers do that in junior high games I ref, and was just shocked to hear it from a D-I referee.
-End Soapbox-