Having received changes of squawk code changes both VFR and IFR it's one of those things I've always just accepted as an ATC process without carrying much about the reason.
Not exactly true. If they instruct you to squawk and call departure, you have no choice but to do as instructed. Ref: 14 CFR 91.123.
I'm a big fan of services.
On the way out, no -- you're not going to hear "cleared for takeoff" if you don't accept the departure instructions from ground. On the way in, sort of -- even if two-way comm is establish, you cannot disregard any instructions they give you. The only thing that "two-way comm" business is good for is if you call them inbound when approaching the C-space, and they say "Cessna 123, stand by," you can continue inbound, as opposed to Class B airspace where establishment of two-way comm with "Cessna 123, stand by" is not sufficient for entry approval.
You're not "offered" the squawk code; you are instructed to squawk it, and any time you're in controlled airspace and communicating with ATC, you are obligated by 14 CFR 91.123 to comply with any instructions they give you, even if you're operating under VFR.
Not really -- see my post above. They all fit together like a big jigsaw puzzle. You have to look at the whole picture, not one individual piece in isolation. You cannot use one reg intended for one purpose to try to make an end run around another reg intended for something else
No, neither time. I've read elsewhere there's no reason to tie up the freq acknowledging a squawk code, just set it. They will see. Or is that only in conjunction with an instruction to Ident?
