I would guess its legal for day since headlights are not required for day.
Not sure, but even if not technically legal it comes down to how much it's enforced, not that I want to give the LEO's a reason to pull me over, but rocking em around town during the daytime in the summer months I'd think would be ok...
Worst case is they'd pull you over for them and you can take them off in about 5 seconds and put em in the side case, I'm sure if you played dumb and said you didn't know and then pulled them off they'd let you go on your way without the ticket...
I think some tinted windows are also technically illegal as well, but yet everyone has them, so it really comes down to how you roll the dice IMO...
I've only been pulled over on my Connie once, and we talked more about my bike and the mods than anything, and in the end I didn't even get a ticket.