I think even when the intentional offenses are not penalized by others, there's still the penalty -- the failing of self discipline, and the failing of restraining and preventing defilements which will produce karma and will trap one in samasara.
I'd like to share the Buddha's aims for formulating his training rules:
"'In that case, bhikkhus, I will formulate a training rule for the bhikkhus with ten aims in mind: the excellence of the Community, the peace of the Community, the curbing of the shameless, the comfort of the well-behaved bhikkhus, the restraint of [defilements] related to the present life, the prevention of [defilements] related to the next life, the arousing of faith in the faithless, the increase in the faithful, the establishment of the true Dhamma, and the fostering of discipline."' (BMC p.5)
I'd also like to share the following from www.accesstoinsight.org
"Already during His lifetime, the Buddha made special allowances for different regions (or desa) outside the 'Middle Country' of North India — where He lived and taught. These dealt with both the workings of the Community — for example, a smaller quorum for ordination is allowed in distant parts where there are fewer monks — and practical measures, such as special dispensation for footwear and bathing. (See EV,II,p.173) So there is a precedent for adapting to conditions, but this does not mean the abolishing of any rules [see End Note 6].
The Lord Buddha also left us a set of principles that can still be used as a standard to judge new circumstances. These are known as 'The Great Standards.' Properly used they should protect against a wholesale dilution of the Rule.
This is how the Great Standards are formulated:
"Bhikkhus, whatever I have not objected to, saying, 'This is not allowable,' if it fits in with what is not allowable, if it goes against what is allowable, that is not allowable for you.
"Whatever I have not objected to, saying, 'This is not allowable,' if it fits in with what is allowable, if it goes against what is not allowable, that is allowable for you.
"And whatever I have not permitted, saying, 'This is allowable,' if it fits in with what is not allowable, if it goes against what is allowable, that is not allowable for you.
"And whatever I have not permitted, saying, 'This is allowable,' if it fits in with what is allowable, if it goes against what is not allowable, that is allowable for you." (BMC p.27; see also EV, II, p170)"
Disparate interpretations of the Vinaya rules can lead different communities into claiming that only their understanding is correct and everyone else is wrong. (SeeDisputes.) The Buddhist Monastic Code has this to say:
"There is, of course, a danger in being too independent in interpreting the tradition, in that strongly held opinions can lead to disharmony in the Community... At the same time,... there are many areas on which the Vibha"nga [section of the Vinaya] is unclear and lends itself to a variety of equally valid interpretations. For proof of this, we need only look at the various traditions that have developed in the different Theravadin countries, and even within each country. For some reason, although people tend to be very tolerant of different interpretations of the Dhamma, they can be very intolerant of different interpretations of the Vinaya and can get into heated arguments over minor issues having very little to do with the training of the mind."
Venerable Thanissaro continues by emphasizing:
"...that any interpretation based on a sound reading of the [Paali] Canon should be respected: that each bhikkhu should follow the interpretations of the Community in which he is living, as long as they do not conflict with the Canon, so as to avoid conflict over minor matters in daily life; and that he should also show respect for the differing interpretations of other Communities where they too do not conflict with the Canon, so as to avoid the pitfalls of pride and narrow-mindedness."(BMC p.15)
Metta to all!