I'm the last person to know anything about e-filing, since professional ethics keep me from sharing client data with third parties like Intuit, and from allowing IRS to inspect files of legal clients.  But I did once work with the IRS branch chief responsible for promoting it, back in the late 70s.  We took care of his dog when he was on vacation, he chewed off the corner of our Bicentennial-theme rug.  The dog, not the friend. The whole program is directed at shutting down sole practitioners -- remember the days of bidirectional modems? -- so it might be part of that scheme.  Or maybe, they figure in four days Congress can amend the law retroactively.  But it probably comes from fear that balance-due returns will be stockpiled until April 14, and then shut down the system.  

And I know someone will ask if I file more than 10 returns, so the answer is that I don't file any returns.  That's defined as taking them to the mailbox or Post Office.  I used to do that for a few elderly widows, but now I just provide envelopes to everyone.