This tosefta assumes that tax and customs collectors are sinners and that they are Jewish. Tax and customs collectors usually transferred a certain sum to the government and then gained profits from the extra money or produce they collected. According to this text, in order to repent from their sin they need to return what they have collected (at least the extra), since their activity is considered as robbery. The text admits, however, that it is difficult to identify the people from whom they took the taxes and determine what should be returned to each. This passage, along with other rabbinic sources, views tax and customs collectors negatively, presents their activity as sinful, and considers it illegitimate. In the Jerusalem TalmudBaba Metzia 6:5, 11a, one finds an almost identical parallel to this text:

הגבאין והמוכסין תשובתן קשה. הרי אלו מחזירין למי שמכירין. ולמי שאין מכירין יעשו מהן צרכי ציבור.

Translation: The repentance of tax and customs collectors is difficult – they return [what they collected] to those they know and to those they do not know, they will use [those resources] for the public good [literally: the needs of the public].