That article doesn’t reference the MA law. This law reference says fine is $100. Not sure if the right law.The Maine registration is not technically legal if you use it in the state of ma
Headed north for trailer registration? You may be sorry! - The Dowd Agencies
Even for a Massachusetts native, there are plenty of reasons to visit New England’s northernmost state. Go for the legendary lobstah. Check out the vast beaches or historic hiking trails. Shop the famed outlets, and score your favorite fashions for less. But if you’re looking to score a bargain...www.dowd.com
Have a utility trailer bought new as a kit. It came with a Certificate Of Origin - which I can’t find. Probably have to register as home built. $22 in NH or $20 in MA plus sales tax.
My personal experience is that police politely ignore boat and utility trailers. Sold a double axle boat trailer to a guy in RI and he towed it home with no plate at all. We towed a boat down from Canada with an expired Ontario plate and no one cared, even Customs: thry just wanted to see the boat paperwork.