For example (extreme examples help make the point) if a person knows from past experience that EVERYTIME he hangs out with a particular group of people that he gets drunk (looses his reason) (they influence him that much…but he still freely chooses it)…so if knowing that he were to still decide to hang out them …that would already be a sinful decision…for he knows that he will end up getting drunk…
as for the firm resolution to avoid near occasions of sin…yes because we have to avoid mortal sins particularly…but also yes in the case of those near occasions that would be gravely sinful for us to be in anyhow …
