The indefinite look back is only for certain disqualifying offenses. Most (many of which are still rather serious) are 7 years. http://www.mass.gov/eea/docs/dpu/transportation-network-comp...
G.L. c. 272, §7 (Support From, or Sharing, Earnings of Prostitute)
G.L. c. 272, §12 (Procuring Person to Practice, or Enter a Place for Prostitution; Employment Office Procuring Person)
G.L. c. 272, § 16 (Open and Gross Lewdness and Lascivious Behavior)
G.L. c. 272, §53 (Indecent Exposure)
G.L. c. 272, §53 (Accosting or Annoying a Person of the Opposite Sex)
G.L. c. 272, §53A (Engaging in Sexual Conduct for a Fee)
G.L. c. 272, §105 (Upskirting)