We do answer questions for free, however we do spend our time to make high quality answers and build them aesthetically attractive.
The only things we get back for our efforts are virtual bounties - i.e. scores and badges. If they are unimportant let's eliminate them. However, they ARE important, by them we and others know who answer the question and how the answer is valid and reliable (I hope).
Sometimes, the OPs with reputation of 1 point just don't realise these facts and allow to themselves just to comment: "Thanks! I spent hours to find the answer" and not upvote or accept any answer at all.
So, the question is - is it ethical for us to ask the OP to upvote or accept the answer if the OP is satisfied and commented about that?
Let's see an example -
I spent 30 minutes for searching data and building the answer, so probably, IF, the OP found the answer useful (by commenting), can I ask to upvote or... as Scott said don't be a moron worrying about ratings, points, badges etc. (Scott, I changed your sentence a little bit for the amplification purposes :))