He's justified his trip as a personal travel, which falls outside of the state law.
The question about California teams traveling to banned states has come up before. I've read in the past that if push comes to shove, away games could be funded through boosters as "private" or "personal" travel outside of school funding. So for example, if noted celebrity I.Luve California provides a private, chartered 767 to UCLA to travel to and from Arizona, and also pays for hotel and incidentals, that would be the way around the law.
This article mentions it as well - they can
likely still travel as long as they do not use state travel.
Aside from an ongoing lawsuit, it's the first backlash to the new law since it went into effect July 1.
www.indystar.com