Are you talking about perpetual check? Then you play it out unless you offer a draw and your opponent accepts.
Forcing a draw
If I'm playing a friendly game I usually don't go for draws even if it is possible. I can imagine in competitive environments though, that its most certainly encouraged to force a draw if your position is weak. Heck, I think today's World Championship Game is an example of that. :)

I was just wondering, how ethical would it be to force a draw by continuously repeating two board positions, continuously keeping the opponent's King in check, until both parties agree that the game will not progress?
I personally don't see anything wrong with this; if you have so few pieces left that there is only one way in and out of check, it may as well be a draw; but I was just wondering what the Chess community's opinion as a whole on the matter is.
Yeah I think it's completely fine as well
I was just wondering, how ethical would it be to force a draw by continuously repeating two board positions, continuously keeping the opponent's King in check, until both parties agree that the game will not progress?
I personally don't see anything wrong with this; if you have so few pieces left that there is only one way in and out of check, it may as well be a draw; but I was just wondering what the Chess community's opinion as a whole on the matter is.