[mcguire]

Then no decision would be made, which is a decision.

When was the last time someone got a supermajority with more than a small number of voters?

[baddox]

Presumably different referenda would be put to a vote if a supermajority were required, namely, ones that are less controversial.

[RugnirViking]

To be fair in some situations where it is not internal political pressure that caused the vote in the first place, large majorities can occur; see the falkland islands referendum on joining argentina