I attended the Queen concert in Brussels, Belgium on 16. April 1978 (or 17. April but I think it was the 16th).
I can not explain it very well (my English is not that good) but when the concert started there was a big problem with the crown that was going up. The right side was going up but the left side of the big crown stayed down. The band members were a bit confused and it was clearly they were afraid the the crown was coming (falling) down again so they were not standing under the crown while they were performing the fast version of We Will Rock You. Also the public was a bit confused. Every one saw this was not an normal situation.
After playing the fast version of We Will Rock You Freddie excused himself for the technical problems and he promised to set this right by playing an extra long concert. Which they did!
During the second song of the concert the crown came down again and was immediatly lifted up again and now everthing worked out well and safely! I can remember while I was sitting in my classroom at the Sint Norbertus School in Antwerp a couple of days before the concert that a huge robot which is on the News of the World sleeve came by. The robot was towed by a truck and it was VERY impressive to see. Every one at school talked about that robot.
The two Queen shows in Brussels were sold out immediately and a 3rd show was added a couple of days later. I was at all 3 shows.