That's not correct. It will continue to run down the valve stem after the engine is running and just get burned up. It can cause the engine to consume quite a bit of oil. I have seen them burn several quarts of oil in a day of boating.
Eddie

In your case the seals and guides must have had a major problem, paired with either a large cam and/or headers to produce scavanging. If it was seals causing your motor to consume QUARTS of oil a day intake seals were most likely the main culprit due to the fact the vacuum of the engine sucks in the oil as it runs. Pistons/rings/cylinder problems also obviously show smoke during the course of running as the oil is slung onto the cylinder walls. Exhaust valve seals and guides usually will only leak oil a notable amount after the motor is shut down and the oil is laying in the rocker valley. The exhaust backpressure for the most part will keep the oil in the rocker area and exhaust can actually make it past the seal and appear as blow blow. I have no doubt that it is possible, but before you say I am incorrect you have to admit that whatever motor you are talking about had a major problem going on to consume that much oil. What I stated applies to the topic starter as he does not have a major problem just a little seaping while sitting.

Well, it wasn't one of mine. I said I have seen it. It was someone else's build. The engine leaked under 3% and all of the guides were in excellent shape. Engine ran like a top, it just burned oil. Go figure.

Most times but not always//For years I didn't even run seals in the exhaust valves with no smoke ever.Added valve covers with spring oilers and started drinking oil.
On the intake stroke the exhaust and intake will see negitive pressure,, Stuck or worn rings will also cause smoke on start up..This is caused by the engine negitive cyclinder vacuum before its fired causing reverse suck by.

Well, i'd like to think optimistic, and keep it simple and say the seals are seaping.........