Thanks, Bob.  That was my thinking as well.  We'll see what happens in the real world.  I told the client to keep an eye out on their bank account and if the "wrong" amount shows up (direct deposit) they should call the bank and try to reject it.  In my case it's only ~$500 in tax so I don't care too much either way and this one was my f-up so I'll cover interest and penalties if there are any.