FWIW a/c lights are virtually invisible during daylight, especially somewhere sunny. Strobes are useless during daytime, much better when it starts to drop dark. Landing lights are OK for head on collision avoidance but not for much else. I've no idea why they would keep them on during the day, I would be interested to know. There's always the possibility they forgot to turn them off, more than once I've reached to switch them on and thought 'Ahhh'....
. Mind you I'm not a professional pilot.