Well, I stand by what I said in the thread you linked to regarding unfair and deceptive practices.  In general, it really comes down to a common sense reasonable person approach.  The court will try to determine if what the merchant or business did would smell funny to the average person. (Sorry for the overly technical language).  There are some general regulations in 940 CMR 3.16 that attempt to offer more clarity, but you will not find any definite answers here:
 
Without limiting the scope of any other rule, regulation or statute, an act or practice is a violation of M.G.L. c.93A, s. 2 if:
(1) It is oppressive or otherwise unconscionable in any respect; or
(2) Any person or other legal entity subject to this act fails to disclose to a buyer or prospective buyer any fact, the disclosure of which may have influenced the buyer or prospective buyer not to enter into the transaction; or
(3) It fails to comply with existing statutes, rules, regulations or laws, meant for the protection of the public's health, safety, or welfare promulgated by the Commonwealth or any political subdivision thereof intended to provide the consumers of this Commonwealth protection; or
(4) It violates the Federal Trade Commission Act, the Federal Consumer Credit Protection Act or other Federal consumer protection statutes within the purview of M.G.L. c. 93A, s. 2
 
However, the landlord/tenant relationship is one of a handful of consumer relationships about which the state has promulgated specific regulations.  You didn't give any specifics about your situation, so try following this link for the regulations.  Good luck.