Dear Miss Manners

I’m curious about proper etiquette in a situation at work. There is a gentleman in another department who, apart from occasional encounters in the breakroom or mens room I’ve never met and do not know his name. This gentleman seems a rather pleasant, jovial fellow, as he is frequently heard whistling in the foyer and the bathroom. He is particularly fond of “If I Only Had a Brain” from The Wizard of Oz.

Here’s my conundrum: He whistles everything except the part that is actually performed by a whistle in the song. It practically cries out for that part to be added.

So here’s my question: Is it acceptable to insert oneself uninvited into someone else’s impromptu public performance? He’s quite good, and I absolutely itch to join in and at the very least insert the missing part. But I’m afraid this might be a social faux pas. What do you think?

— Would-Be Wasatch Whistler