JD
I don't disagree with what you're saying but I have had - or heard - a number of experiences of being told "report approaching southern airfield boundary" which have then led to "orbit present position till advised", and also occasions when an unnecessary but inaccurate readback of a request to "report approaching southern airfield boundary" as "report southern airfield boundary" has led to an ATC correction - with the clear implication that the Tower controller is anticipating holding you at/before the aerodrome boundary if there's conflicting traffic.
With that experience in mind I tend to take a rather liberal interpretaton of "approaching" so that I get told whatever ATC wants me to do before I get to the position where I need to do it.
In my view there are regularly lots of opportunities for misunderstanding between ATC and pilots when there is a mix of VFR and IFR traffic within the ATZ. When you operate regularly in this environment you become experienced at predicting the Tower controller's plan, but it can be quite difficult. Worst examples are clearances to VFR traffic which put them head to head in the same patch of airspace, without consideration to how difficult it might be for the pilots to apply see and avoid.
NS