Withdrawing a readied action

[Vakil Smallen]

So, one of my players readied an action that says the following:

"Ready Action: Evil Eye vs Attack, Evil Eye DC16 or -2 attack for 8 turns, mind-affecting.
Trigger's just going to be having any sort of hostile-looking target."

Well, in the next round, a previously unseen enemy (an ettercap on the roof) drops a dead body into room. It lands right next to the player with the readied action, invoking a save vs fortitude or the player is sickened.

I'm wondering if I should have him use the readied action on the dead body, which is a hostile, if inanimate, target. Certainly, dropping from the ceiling implies an attack. What I would do is make him roll a perception check with a DC of 10 to see if he realizes what it is before he uses his readied action. Does this seem fair?

[Are]

A player isn't required to use the readied action if he/she doesn't wish to do so (bolding is mine):

PRD wrote:

Then, anytime before your next action, you may take the readied action in response to that condition.

However, a perception check to notice that the dropped body appears to be dead/unconscious seems fair. Then, it would be up to the player/PC to determine if he/she wants to attempt the action.

[thenobledrake]

Are is right.

It is important to note, however, that you don't get to do something else if you choose not to follow through with your readied action - effectively "wasting" the action.

[Bobson]

Both Are and thenobledrake are right, but it's worth pointing out that the action isn't "wasted" the first time you choose not to follow through on it. It's still considered ready until you take it or your next turn. So you can ready to shoot someone casting a spell, but wait for the second or third person to do so... if they do.