As far as I can tell, most of the thorough inspection in Maine is the inspection place doing extra "free" inspection work to try to find stuff even slightly wrong with your car. Not only will they claim it fails inspection (although they're not doing required checks), they obviously hope you'll get the car fixed in the same place. It took a while for me to find somewhere that just did the basic inspection. I have heard others have the same experience. I've never seen this in MA.
Also note that Cumberland county has slightly different inspection requirements and you must get your car tested in that county if the car is registered in that county. Only in Maine...