Ooh, sorry, I missed this. Yes, works great on my real NTSC machine!
As for video detection, I actively avoid situations where I'd have to care about the video system in use. But I feel like I'd probably approach it by offering two versions of my program and letting the humans sort it out.
I recently bought a copy of Astro Nell on cassette, and it doesn't work on my NTSC machine. That it's made for PAL is just not something that they cared to mention. So, I'd say, thinking about it at all is a considerate move.