But they do not have the right to have a blockade in which "the damage to the civilian population is, or may be expected to be, excessive in relation to the concrete and direct military advantage anticipated from the blockade.", per section 102 of the San Remo manual. Here's a link .http://www.icrc.org/web/eng/siteeng0.nsf/html/57JMSU If you read it, you will also notice other criteria that Israel has not followed, in order for this to be considered a legal blockade. By the way, the Pals also have a right to defend themselves. As do Turks on civilian ships attacked while in International waters in the middle of the night by commandos trying to enforce an illegal blockade..
Colombia recalls ambassador to Venezuela amid border crisis (Reuters)
from the article: Libya-sponsored aid ship originally headed for Gaza enters Egypt port