For a conservative, the hazards of speaking on a college campus are more extensive than you might think. Once the security guards are in place – as they inevitably must be – the risk of getting pied or physically attacked or having one’s speech shut down by raucous protesters is actually a lesser problem than others one regularly encounters at these events.
Far greater is the problem presented by the generally hostile environment a conservative normally encounters on any campus. This includes destruction of flyers advertising one’s event, failure of the campus newspaper to publicize it and failure of professors to recommend or even require student attendance as they regularly do for radical speakers.
I have very little experience as a university student, but I do recall that the worst professor I ever had, and one of the worst humans I've ever dealt with, offered extra credit if we'd attend a talk by liar Rigoberta Menchu--and the class involved had nothing to do with writing, with the Maya in Guatemala, or with Latin American history or politics. I don't imagine many professors offer extra credit if their students go to a talk by David Horowitz or Mike Adams.