Brooks,
This is a great question...still.
The simple answer is to insist that players announce exactly what they are doing. However, that would be to simple, so it rarely happens.

I looked back at the two links you referenced and wanted to change my own answers!

Taking back your short bet or blind first, before tossing in the oversize chip, would make it much easier to enforce the oversize chip rule. The problem, in my opinion, is when the player leaves his short bet or blind in the betting area and then adds the oversize chip. I realize, I'm not answering your question, just clarifying that I do understand the situation that you speak of.
Unless the TDA comes up with a specific "firm" rule...this will always create controversy. TDA Rules #'s45, 46, and 47 all pertain to this situation but still allow the floor to call it either way. I'm sure it could be easily fixed...possibly not to everyone's liking...but it could be corrected.
Example: Players faced with a situation when more chips are required to either complete a bet or raise, or to raise a specific amount, are encouraged to announce their intentions before adding chips to an existing blind, or an incomplete existing wager. Failure to declare a raise, before adding an oversize chip, will disallow the raise and the oversize chip rule will apply.
Or:
Players faced with a situation when more chips are required to complete a bet or raise, or to raise a specific amount, MUST announce their intentions before adding chips to an existing blind, or an incomplete wager. Failure to remove an existing short bet or blind without clear declaration will automatically be recognized as a raise to the sum of all chips.
That's it...one or the other.
