Jasper,
I mentioned the possible actions because Chet wrote: "I have a more difficult time defining the term "already acted" and trying to explain that to the players."
And you wrote: "As I see it, #37 is specifically speaking of "Raises". So that a Raise has to be of "Full" or "Legal" size in order to open the betting to a previous player. The already acted part is easy here because, well, anybody that has checked can't be getting raised can they?
The answer to your question, a player that checked can't be raised, is true. However, you must also have a legal (full) bet before a player can raise. A short all-in has the same effect, as a check.
I also want to say that I don't like going to the dictionary to try and understand what the hell you're trying to say, especially when it isn't even a word ???non sequitir?
ENGLISH ONLY!

I like all of the suggestions that were made. This one should have been addressed long ago.