A cinema is private property, as someone else has said above, and the owners have the right to set out terms and conditions of access to that property, just like shopping malls (remember the "no hoodies" rule at Bluewater?). If there was a sign saying they could search bags, then that is one of the terms and conditions of entry, and the fact that they might not have done searches in the past does not mean that they can't do them now. If you don't like the terms and conditions of entry, you can choose not to go in. Your complaint here seems to be with the way in which the search was carried out, and that is something you can complain about to the management, but you can't complain that they shouldn't have done it *at all*. So in answer to your question "is this legal"?, it is legal, but it sounRAB as if they didn't do it very well, which is a customer service issue rather than a legal issue.