Well, considering "Kill Counter" automatically accepts the invite to get into Cyrodil when you're queued I can't imagine it would be too difficult to extend it to BGs
That being said, getting kicked from Cyro for being idle isn't as experience ruining for other people as it would be in BGs
Actually, yes, it is possible to write an addon to automatically accept the ready check.
(Needless to say, this would not be a good idea. "Hey, what's that guy doing at the spawn point?" "I think he's AFK." "How did he accept the ready check?")
Should be simple to write. Might be considered botting. Sorry, I’ve never played BG or I might have something useful to add. I have wrote a couple of addons to fix some gaps in game. Not to be published. Wish ZOS would better document the API.