too late, i already opened it. opened it several times, in fact, in an effort to blow out sediment. the dripping has stopped, but that might only be temporary.
i respect your 20 years in the business, but i have been told by plumbers that it's a good thing to try.
here's a guy who says it's okay, but he's only been a plumber for 10 years!
"P/T Valve on Gas Heater is Leaking
Q: Intermittent leak from pressure-temperature valve PT valve new with heater and heater has a surge tank already installed to absorb surges in water pressure. I turned the temperature setting down, it helps some but run out of hot water too fast!
A: It could be a couple of things. Although it is only 1-1/2 years old the safety valve could be bad, which means it needs to be replaced? Most likely sediment has built up around the valve. Try flushing it out. Place a bucket under the blow down tube from the valve. Quickly open and close the valve a couple of times to clean it out. If it still leaks replace the valve."