Should you tell Tower you're departing IFR

S Narayan wrote:

I don't see a big difference in the time taken from saying "Ready for
takeoff" to saying "Holding for IFR release".

I usually say "ready to go, IFR". I also mention that I'm IFR when I
request my taxi instructions. I'd prefer an extra half-second of radio
time to the possibility of confusion.

KCDW modified their procedures a while back in a similar way. They no
longer provide the squawk code with the clearance information; it's
[almost] always "clearance on release". I asked once, and was told that
there was a problem with people taking off IFR and the tower not realizing
they were IFR. Holding back the squawk apparently blocks that.

*Why* (or "how") this occurred is a part of the back story that -
unfortunately - I was not told. I'm still curious, should anyone here
know.

- Andrew