It is very risky as a candidate to talk to people when you don't know what they will say or do, when cameras are rolling, which is why they plant people with known, planted questions. So it sounds a bit suspicious that he would randomly walk over to people who support another candidate and talk to them with cameras rolling.
Any idea how annoying that is on a discussion Forum?
... are you positive that these Trump supporters are actual Trump supporters?
You owe it to yourself to watch those people's unrehearsed contempt for Cruz's lying. It's very doubtful a rational person would have set himself up for that. He was expecting irrational violence, believing himself their moral superior. What he got was a richly-deserved helping of moral discernment from the "common man", and rejection of his patronizing beliefs about them.