Ha! nice.

I think the idea is that the flatmate who can't stand flushing is the first one to wake up

Or buy a fan. The white noise will cover the sound.

"Flush him out." probably would've been better. lol

If this was a story involving living with family, fine. But roommates are a different story. Everyone is paying rent and no one should have to view another person's waste because one person is a "light sleeper ". Ask to switch rooms to one further from the toilet, wear ear plugs, play background music to drown out the sound, or move the hell out. It's just not fair to paying individuals to have their personal bodily functions limited in their own home. To be honest you would think that someone who's that light of a sleeper would say something prior to moving in and find out this isn't the right arrangement for them.

Fair enough.

Urine has an unpleasant odor too. That's thoroughly disgusting, and increases the chance of sickness.

There are many areas of the world where flushing urine diverts water from more important uses, including areas of the US at times. Would you rather have a sparkling toilet all of the time, or water for drinking/laundry?

Considering that isn't a problem where I live, I'll take both.