BB is right although retrospective motions can work if they put things right on paper (ie, maintenance of changes to common property become the responsibility of the current and future lot owners, provided they don't transgress other by-laws).
But they shouldn't be used to rubber-stamp common property land grabs or by-law breaches. That's one of the reasons that enforcement of by-laws should be made compulsory in this state … so that the controlling cliques can't pick and choose what to enforce or who should get away with what.