Would attending this pose a security risk to him? Perhaps the event isn't being held in a location conducive to setting up and maintaining adequate security measures.
These trials could provide a convenient cover, shielding him from potential threats of assassination if he were to attend.
How often has Trump been legally prohibited from attending family events?
Sometimes a cigar is just a cigar and a piece of shit judge is just a piece of shit judge.
Probably the later :D