I subscribe to the ® AFK agreement (see Forum topic The Case for AFK Arena Duels). If you also have an ® in your motto and you are in the current list of AFK players in the above thread* then, except for prayers, I will be AFK as long as you are also AFK and we will let The Random decide the winner.
If you do not have an ® in your motto then everything is normal and I will attack, defend, etc as I see fit.
* (I am aware that following bad advice from certain parties in Harvest Moon, some unlisted people use the ® as a subterfuge and hope to win by possuming. If I suspect subterfuge, all bets are off.)