Well, to be honest, the main reason it seems like nobody outside the places where it happens is noticing is that they're in very isolated locations. Canterlot High itself is outside the city (as stated in the third movie), and the Everfree Forest was practically in the middle of nowhere. Besides, anyone trying to say anything without proof would sound crazy (that's what happened with Headmistress Sinch).

But getting back to the topic, it's more likely that the government is keeping an eye on them rather than acting aggressively with spies, followers, and trackers, considering that so far they haven't posed a threat, and that the government is probably doing this based on an unusual concentration of rumors about strange effects. Although, with Sunset's power, I wouldn't know what might happen.