I've never seen anyone kicked out of a Dream Theater concert for taking videos or photos, but, at almost every show I've been to, security is constantly telling people to stop doing so. Interestingly, prior to the start of almost all, if not all, of the Dream Theater shows I've attended, there is typically an announcement that the venue's policy prohibits photos and videos during the show. However, when I've seen other bands at the same venues, there is no such announcement or enforcement.