Is “maybe not” more helpful?

Probably, or maybe not. Change your answer and see how the helpfuls change.

I totally agree with the other answers given. Just to reinforce a definite MAYBE, it should be noted that the statute of limitations does not begin to run until the tax return is filed. If you bothered to prepare a return, file the return. I lean more toward an answer of YES. 

Of course then comes the problem of the original question:  The OP asked if he needs to E-FILE the tax return.  E-filing is closed until mid-to-late January, so it probably should be mailed.

OR just wait until the gates open in January. Late is late and assuming the "doesn't owe any tax" is still true, there is no rush. I like the confirmation of receipt we get with e-file, so I would wait.
This is not one of the hardest decisions a preparer will face, but I understand the challenge.

I Would e-file the return so it will be on record that The client owed nothing for the year in question