accept game offer

When someone issues an open invite, why is it that with some player's invites there is "accept game offer," to click on, which makes it very easy to accept the game, but not with other player's names? How do you accept an open invite from a player who doesn't have "accept game offer" to click on?

Originally posted by AttilaTheHorn
When someone issues an open invite, why is it that with some player's invites there is "accept game offer," to click on, which makes it very easy to accept the game, but not with other player's names? How do you accept an open invite from a player who doesn't have "accept game offer" to click on?