Actually, umbrella's were allowed. Small camera's were allowed. Nothing was checked, we even brought some snacks/food and could have taken drinks.
We just got home in Eindhoven with my girlfriend, returned from Amsterdam. It was in one word WONDERFUL. In more words, the weather was great (just a few drops of rain, didn't need any raincoats), the people were friendly, we even got to park our car on the other site of the entrance (we were a bit early and sat there with the first 15 or so people) and a few hours later, Leonard Cohen and his friends were superb! The sound was good, his voice was more than ok, we got to stand 10 meters from the master himself, so we could see every detail of his wonderful smile, which he showed a lot during the performance...
Going to sleep now, with a smile on my face myself!