I've previously suggested that majorities should have a margin of safety so that, for example, the vote can only be passed if the split is 52% to 48%, or greater and not if the vote is 51% to 49%. This allows for errors in the voting system.
However, the bigger the safety margin used, the more likely is the situation that the vote will be "hung" and the issue unresolved: a stalemate that could hamstring politics. It is therefore important to make sure that the voting system is accurate and without corruption, so that margins of safety don't need to be broad. If ballots are still indecisive it may be prudent to give parliament the carrying vote.