AZ may be the last straw. Trump will then need about 50% of remaining delegates while Cruz would need about 80% (I'm too lazy to be more exact.)
This article makes a good point.
Playing politics at the convention to deny Trump would be a huge mistake IMHO. Trump voters may not riot, but they are certainly ready to take on the elites in some capacity. How much injustice will they tolerate? Make no doubt, majority doesn't mean half in a multi-way race.
Oh, and saying more voted against than for ignores the reality. That argument is only valid in a pure two person race.