I checked the laws in other states and I saw no state that had both permitless carry and a duty to notify, despite claims to the contrary earlier in this thread. There may have been a time when states had duty to inform and no requirement for a permit but not now. I've been told that Maine could pass this law and fix the duty to inform later, and that is true. What I'm saying is that so long as the duty to inform exists the permitless carry law would be a hollow victory.
Given that a Maine concealed carry permit would be required under existing federal law in order to possess a firearm within 1,000 foot of a school zone (and these school zones are unmarked and everywhere, especially in cities), one could reasonably argue that they have no legal obligation to potentially incriminate themselves (thus no duty to inform).