So you request good sportsmanship from your opponent, but you are trying to annoy him if he uses his time to think about a problem.
Wasting my time in a completely dead position isn't good sportsmanship, in fact it's even worse because they can just resign at any point to finish the game while I have to slowly run them down
My first post in other words:
You are not a good sportsman if you expect your opponent to resign because of your impatience.
Just my point of view.
1st advice: this tip OP suggested will not work on almost any stallers, especially if they are already unsportmanship themselves. They will be more happy if you do what OP suggested. And infact its time consuming. Instead play normally and report your opponent and move on. Its time consuming, I know, but it will save more time than the tip OP suggested. Thank you.