Now that I think of it, rests during pieces I played on the bass weren't the only times I heard Watchcat Rusty sing. There was at least one other occasion. When I played Herb Ellis and Duke Robillard's version of "Avalon" on the stereo, Rusty started tapping his tail and let out a sung "Meowwwwwwwww!" in conjunction with the guitars.
How can you not respect a watchcat who has the good taste to appreciate a well-played swing guitar cover?