In May 2010, the Mavi Marmara was about 80 miles from shore and Israel had a 12-mile limit, but there's no question that it was headed for Gaza. Israel's right to intercept and detain any ship attempting to break the siege or blockade of Gaza is hardly clear at all. Guests of the radio show Democracy Now, Huwaida Arrat and Norman Finklestein, strongly dispute that Israel had any such right.
Essentially, the proposed compromise is that Israel could check incoming shipments for weapons, but could not otherwise stop imports. That has the problem of defining a weapon. According to Israel, cement (Freedom Flotilla II had lots of cement onboard), which is widely used as a construction material for housing in the region, is also useful for constructing fortifications. The distinction between imports via land and via sea differ only in that imports via land can be checked more easily.
The UN Special Rapporteur for Human Rights in the Occupied Palestinian Territories writes for Uruknet that, in the case of the report of the Palmer panel, that "the report failed to address the central international law issues in a credible and satisfactory manner."
But to be satisfactory, the report had to interpret the legal issues in a reasonable and responsible manner. This meant, above all else, that the underlying blockade imposed more than four years ago on the 1.5 million Palestinians living in Gaza was unlawful, and should be immediately lifted. On this basis, the enforcement by way of the 31 May attacks were unlawful, an offense aggravated by being the gross interference with freedom of navigation on the high seas, and further aggravated by producing nine deaths among the humanitarian workers and peace activists on the Mavi Marmara and by Israeli harassing and abusive behavior toward the rest of the passengers. Such conclusions should have been 'no brainers' for the panel, so obvious were these determinations from the perspective of international law as to leave little room for reasonable doubt.
China's news service says that "Ankara announced a series of measures against Israel, which included downgrading Turkish-Israeli diplomatic ties to the second-secretary level, suspending bilateral military agreements, and demanding a review of the Israeli blockade of Gaza by the International Court of Justice."