they have to pay financial compensation for any damage caused, also for the deployment of israeli forces to the site (fire workers, army, police, investigation...). if they repeatedly fail to bring terrorists to justice, this will have consequences, and they might loose their statehood in the end. besides any sympathies left. from the moment, israel plays according to the rules (legalized borders, no settlements, withdrawal from the declared palestinian state), the pressure on "palestine" will be enormous, from the whole world - including the arab. now, due to israels "occupation", there is a not all negative view on most of the palestinians, and arab states might feel to take party for their case. but when this new official state, after all their "fight" for it, continues terrorising israel, and therefore the whole region again, then they would be done...
Saudi FM: We hope Iran uses sanction relief for development, not nefarious activities (Reuters)
from the article: What would happen if Palestinians unilaterally declared statehood?