I was googling for straws the other day and noticed the above search suggestions.
Number 2 caught my eye and piqued my curiosity.
After three hours of research, here's the best answer I found:
The melting ice acts as a slow, continuous flush.
Ice cools the air around the urinal. Cool air sinks, which serves to contain the smell.
Cold discourages drain flies.
Fun to melt, helps users aim better, compensates for poor male sanitary habits.
Imagine if that hypothesis is correct, that urinal ice's prime function is a sanitary one. If an unwitting game of *pee target practice* really keeps the floors clear(er)....then human males might even be more pathetic than anyone had previously thought!
Many women have rarely, if ever, been in a men's comfort station - so they don't know how nasty the floor is, how poor and indifferent aimers men, aged 3-93, really are.
So I'll let Paulie Walnuts colorfully elaborate; and he does in fact address the ice: (WARNING: adult language )