How would you propose to proceed if someone uses the generic phrase in a published sentence i.e. "How can I get Maine CWP training?" or a thread titled Maine CWP Training that would list those offering such service?
Trademarks are relatively easy to get by claiming to be the first or only one to use the specific wording or symbol, especially when there is no one objecting. I do not see how you could claim exclusivity in this case however and do not believe it will hold up to a challenge.