Doesn't happen. I mean the uncontrolled flashing fixture, this is one of those cases where a small impedance mismatch doesn't have any effect. Wireless DMX.. now that is another story.
Yes, it does. Don't let the lack of failure lead to think everything is fine.
Perhaps on the scale of a band doing lights at the pub you might not have routine trouble but you just haven't found the troublesome combination of cables & fixtures that sends various lights off into their own little world... give it time, Paul. You *will* have this happen.