When to play fowl

Bill Green, in his current post about bigger logos that work, says “Most clients need something to comment on in a layout”, which reminds me of a certain practice that I know is occasionally used here. It’s called the Blue Duck Solution. I’m sure it has a more profound name at other agencies.
The idea is very simple.
When you know the work is absolutely perfect and the client just has to find something wrong with it, then hide an obvious anomaly that is only just hard enough to miss at first glance.
The client spots it. The art director and account director slap their own foreheads in a revelatory manner and congratulate the clever client. The anomaly is removed and the client is pleased.
Job done.
Here is a crude example I have just cobbled together.

(Click image to enlarge)