1) Why would you stop? If you rarely downvote otherwise, then you can downvote several spam in a row and have no risk of losing any XP.
That's fine. It wasn't clear to me late at night that the average was taken over a long enough period that a few days of downvoting spam wouldn't mean I was doing - or seen to be doing - the wrong thing.
So do you have a pathological devotion to never losing a single XP that you'd rather see spam stay longer just to avoid losing 1 or 2 XP?
No, but I DO have a pathological devotion to doing the right thing! :-) If I AM doing the right thing by downvoting spam, I'll keep doing it. But given that you want to discourage problematic voting, I wanted to clarify whether my voting was problematic, given that I'm not at a level where I can 'consider' nodes.
2) Up-voting a few nodes by the same author is not punished.
Got it. Again, I'm concerned about avoiding being a problem rather than anything else.