I am actually creating the keynote on the Mac and then transferring it to the iPads.
In that case you should test these settings in Keynote Mac:
Inspector > Document > Document > Automatically Play on Open
Inspector Document > Document > Document > Require Password to Exit
You should also read this Apple note: Creating on Mac, Presenting on iPad
I have no idea if the iOS version has these settings, or if these settings will transfer to the iPad, many do not.
Very few iPad users frequent this discussion, we appear to be dedicated Mac users here.