Is it appropriate to ask the OP of a question to select your answer as the selected answer when you know that s/he has entirely understood your answer and that s/he is satisifed by it in the comments?
For example: in this answer I completely explained the mechanics of the pulley sliding on the table and one can see that this accurately answers the OP's questions from the comments. Is it okay for me to remind the OP to choose my answer as the selected answer?
It's perfectly fine and even encouraged to remind a poster of SE etiquette, in particular that they should upvote helpful answers and accept the best one that directly answered their question, if there is one. But it's not OK to tell someone how to vote or which answer to accept.
To take the actual example from the answer you're asking about, the comment you posted:
Also, since you've understood the answer, mark this as this as the accepted answer by clicking the checkbox on side.
is not appropriate. But this would be fine:
If you think this is the best answer, could you mark it as the accepted answer by clicking the checkbox on the side?
This isn't something that gets you in trouble just for doing it once, but if we notice someone repeatedly making the former sort of comment (telling people how to vote), that will probably be the basis for some sort of disciplinary action.
