Placing Note Block above liquids for a "Whistle" sound

What does a pot do when it comes to a boil? It whistles! 

Whistles features in lots of songs, old and new. Currently, we have no way of making a whistle sound in Minecraft, much less with a note block. Note Blocks give the sound of an instrument depending on what's underneath it, but currently it does nothing with liquids!

I think it would be really cool and handy if placing a Note Block above a liquid (currently our 2 liquids are Water and Lava) would result in it making a humanish whistle sound. As liquids are also kind of annoying to work with placement-wise, filled cauldrons can also be used for the same effect. What do you think?