Its an idea about UI, not macros. The behavior can be disabled if there is a macro running. I don't see how this really creates more confusion than "Ctrl-C with no selection copies the line".
I am looking at v17 interface right now and there is no item I can see to copy the filename. Nor do I see a copy-filename macro that ships.
Surely that creates some frustration.
It could also be a smart-paste, pasting as the proper #include or <script format according to doc types.
Come on now, don't be such a poopy-pants. 
A couple ways off the top of my head in v17:
- right click a file tab and choose "Copy Full Path to Clipboard"
- hit Ctrl+C on a file in the Buffers tab of the Files pane
(I didn't know about the second one until just now -- I just looked at where filenames appear in the UI, and tried an intuitive action and sure enough it worked

.
Copying the current line when there's no selection is highly discoverable -- the cursor is on the line, it follows naturally that hitting Copy will copy the line.
It's hard for me to imagine anyone would think "How can I copy the filename? Oh, I bet if I turn on a phantom top line, move the cursor there, and hit Ctrl+C that would copy the filename...let's see...wow, yeah it sure did, excellent!"

Just to clarify -- I think it's a great brainstorming exercise, it just seems like some refinement could come up with an approach that's discoverable and therefore useful for a broader set of people. (Btw, disabling the feature while recording a macro introduces an inconsistency, making it more complicated to explain/understand, and for example causing yet another case where playing back a recorded macro doesn't do the same thing as what was originally done).