"apparently at the urging of Palestinian activists and academics" Sources for this? I think he is big enough, and smart enough, to make his own decisions. He is not showing up because he decided not to show up. Not because Palestinians said he shouldn't and Israelis said he should.
Firebomb thrown during demonstration in northern Israeli town of Umm al Fahm (Haaretz)
from the article: ADL: Hawking's Israel boycott a 'slap in face of academic freedom'