In view of NoMat's and BillM16's (and Nick's) comments, perhaps a rule clarification or some specific examples involving blinds in the addendum may be warranted. If there is still confusion, then I can't see why there would be resistance in clarifying the application of the rules in this circumstance. However, I can assure you that at least at the highest levels of tournament play, these scenarios would uniformly be ruled as a call by knowledgable TDs. I believe my explanation and Brian's explanation are sound and reflect the current practice in these situations.
Moving on to NoMat's second example, in the absence of a verbal indication, UTG's wager would similarly be ruled a call. The "removal of a single chip sufficient for a call" concept clarified in the multiple chip betting rule (new in last update) does not apply here since the actual (physical) betting action in question only involves one oversized chip. If, on the other hand, like Brian notes, the player took the chips on the table back and then threw them all back on the table with the big chip together in one action, then the multiple chip betting rule would apply. I can see why there is confusion because the new multiple chip rule does not explicitly distinguish between chips wagered in one action or chips making their way into the pot in multiple chunks over several iterations. Again, all I can say is that most tour and circuit TDs would not treat the situations described as invoking the multiple betting rule.
Personally, I would also note that many players are conditioned to not touch chips once they have been wagered (or the pot for the matter), which means it is not always evident to players that they could even have taken back the 300 -- so I would tend to believe the person was asking for change anyway. As I mentioned before though, unless I suspected an angle, I'd be content to default to the lesser action anyways (call) if there is ambiguity.
I also want to address Bill's note on Rule 44. This rule shouldn't be taken as suggesting that what might otherwise be a calling action should be deemed a raise. That was not the intention of the rule (also new in last update). The "rule" was meant to be a warning that in cases where chips already wagered are before a player, there can be ambiguity. Thus players are encouraged to verbalize their action to avoid a ruling that might be contrary to their intentions.
If memory serves correctly, the history behind this new rule came primarily from a discussion on what would happen when different amounts of chips have been wagered by a blind, and then the blind puts in more chips. Without hashing through all of it again here, I think it's safe to summarize what was meant to be said as this: if the amount already wagered is less than the total amount needed to call (like in NoMat's two examples), and an oversized chip is then thrown in, the action is deemed a call; however, if the amount already wagered is SUFFICIENT to cover the total amount needed to call, and then another oversized chip is thrown in (e.g. if UTG had originally called 300 by throwing in a 1000 chip expecting change, and then, when facing a raise to 800, he then throws in another 1000 chip), this would be a raise. These are examples of different situations involving chips already wagered that I think was contemplated by the new rule; I don't think the rule was ever meant to suggest that one should lean toward ruling something a raise over a call in cases of ambiguity,
All this said, I sympathize with those who are trying to figure out what to do from the language of the rules without the benefit of following the discussion or the history. So yes, maybe an example or two in the addendum would be helpful.