Originally posted by PalynkaWell I disagree strongly.
No. It's their business to accept or not, there's no harm in asking, only in demanding.
I don't think one should EVER ask or suggest it.
Taken from: http://tinyurl.com/n2tl3
Do not ask your opponent to resign
Although it is sometimes annoying when an opponent plays on in a lost position, it is never appropriate to ask an opponent to resign. In this case you should let your chess moves do your talking.
Playing on in a bad position
If you are totally busted then it may be best to resign. If you feel that you can still learn something, still have a defensive resource, the position is complex or can be made complex (inviting a mistake by your opponent) or you are unsure that your opponent really has a won game, you need make no excuses for playing on.
I agree completely with this.