up until abbey road(?) the beatles didn't even turn up for the stereo mixing, all the energy went into the mono mixes, so in answer to the question posed, my answer would be "i'm in the beatles" :-)

I suppose it would work if you were trying to create an accurate mix of a simulated live un-mic'd performance for a film project where character was placed either extreme left or right of screen.

Well, if played in a car it would sound like she was singing to you from the passenger seat :)

"Because I want to" and it wouldn't matter to me who may have done
it before or what anybody else would think about it. If others liked it-good. If not- to bad.
 
 
 

Not related to the panning question, but rather to the artist. As a video game music composer I can't help but mention that Faye Wong is very famous for singing the vocal theme "Eyes On Me" from Final Fantasy VIII. Ignoring the sometimes awkward English lyrics, the song is really quite lovely. Look it up!

Guitarhacker
In my opinion...in short ... "NO".... however......
 
The entire Beatles remastered box set is that way..... vox on one side hard panned, music on the other side also hard panned.... quite the unpleasant surprise and listening experience on headphones. It only sounds good on something that has it's R & L speaker close together.   On the Beatles remaster, I heard that it was a mistake that the vox were left panned hard, and got sent to the reproduction stage before the mistake was caught. They decided to leave it that way for financial reasons,,,,, hoping people would think it was "artistic expression".....
 

But weren't all the original early stereo records of the Beatles just like that? So that is the original way they were made, isn't it?. I've also heard a Beatles record with the drums hard panned on one side. That was because they were recorded as any mono recording, and then made stereo with the means they had.

I can think of a good reason not to: Drums and Guns.  The band you may know, Low, they've made some amazing and some mediocre music over the last 20+ years.  Drums and Guns came out in 2007, recorded with Dave Fridmann (a producer who's been a part of many modern masterpieces), and is almost unlistenable on headphones because of the hard pans.  In almost every track the vocals are split hard right or hard left, a synth or the drums are on the opposite side, with some texture (if anything) in the middle.  It might have worked for The Beatles but it failed Low, which is too bad because Drums and Guns has some great material...just don't try listening to it on headphones.

I imagine that panning a lead vocal could be effective if a theatrical presentation is what is intended. Also, it may be appropriate for duets or an arrangement that involves two or more lead vocalists.
 
 

Well, I am aware of the need for convention, but I am liberated by the ability to defy convention:
 
I hope I am attributing this quote correctly to Moby in EM Magazine:
 
"When I was growing up and first making music and trying to get a contract, I bought into this sort of sad belief … that there was a sonic ideal and every engineer’s goal should be to reach that perfection, finding the perfect kick drum, the perfect snare drum," recalls Moby, speaking by phone from his apartment in New York. "But the more I found people that were striving for technical perfection, the more I found a lot of records sounding the same. Technically perfect records have been being made for modern rock and pop from 1996 until 10 minutes ago. They’re recorded the same, mixed the same, and the only differences are the songs and performers. But listen to Silver Apples, Suicide, early Heaven 17, Kraftwerk, Joy Division, all the way back to The Beatles . . . it was all very sonically different.
"Realizing that suddenly makes the studio a place where the goal is to make something interesting rather than something perfect," continues Moby. "It emancipated me to believe a record can be anything you want. I am perfectly happy with noise and hum and wow and flutter and the things most people consider mistakes; to me, they are just part of the record."

I think I can shed some light on this particular song.
The track appears to be taken from a Karaoke DVD and the way audio is encoded for Karaoke DVD's is unique.  The L/R channels are used for the music and Ls/Rs channels are used for harmony vocal and melody vocal.  In a Karaoke capable DVD player, the Ls/Rs channels are mixed into the L/R channels and the user usually has some control over the volume of the vocal tracks.  A small percentage of Karaoke DVD players also have pan controls for the vocal tracks, but most users found the pan controls to be difficult to use and just wanted to sing and have fun.  The majority of Karaoke players now just route the vocal tracks equally to L/R.
 
So, likely this is a track copied from an improperly set up Karaoke DVD player that has vocal panning.