jmmoric,
You said: "That means he has to maintain 5000' intercept the localizer, and then follow the procedure as soon as he was given the approach clearance."
Lets look at his statement...
"Today, on my approach to KORD, I was given a base vector , an instruction to descent to 5000' and to intercept LOCALIZER to RWY 28C.
When stablished on LOC, at 5000' I was instructed: "CLEARED FOR THE APPROACH 28C".
First off, he never would have given an instruction to intercept the localizer while on a base vector. Lets assume he was flying in from the north downwind... he would have been told, "Boeing744, Heavy, turn right heading 180, descend and maintain 5000 feet." When in position, he would have been told, "Boeing744, Heavy, turn right heading 250, intercept the 28C localizer." The reason he might not have been cleared here are many... Maybe the controller next to him working the 28R final was late in getting his guy turned in, so he asked the 28C guy to just have him join... maybe it is controller technique.. having worked this EXACT operation at two other airports, I have seen it all...
Once he was given his approach clearance, he is free to descend according to the stepdown fixes, REGARDLESS of where the GS is!!!
You said, "Every controller would expect a pilot to maintain 5000' until otherwise cleared... (the approach in this case when he was established)"
Not arguing that point at all. That was not his question though. His question was, "when cleared for the approach, at 5000', should I descent following the steps, and only intercept the GS at 2300' as by the chart, or I can maintain 5000' until I intercept the GS?"
My response was, "To answer your question, it is completely legal for you to descend to those altitudes on the plates as you would normally do with any stepdown fix... however, most controllers are going to expect you to fly at 5000 until you join the GS and then to descend according to it."
I am sorry if that confused you.