It is the responsibility of the members to elect a speaker. And no, the Libs didn't default, as you put it, but they could have. I'm unaware of any "convention" that covers numbers needed for party status, but there certainly is one regarding how a speaker casts a tie-breaking ballot. And no, there won't be a tie regarding acceptance of the Throne Speech now. But there could have been had the premier been a bit more Machiavellian.