Seumas Milne in The Guardian:
In spite of Israel's disengagement in 2005, Gaza remains occupied territory, both legally and in reality. It is the world's largest open-air prison, with land, sea and air access controlled by Israel, which carries out military operations at will.So you can occupy a territory without setting foot on it? Even if Milne's description of the circumstances faced by Gaza were reasonable and complete, which it isn't, it would still be a description of a siege rather than an occupation.
There is, of course, another purpose to Milne's language: to set the meanings of words such that Israel's very existence can be called an 'occupation'.