I can't see the pictures, but I've seen that happen before. When I started SCCA road racing, we were not allowed to weld in roll cages in Showroom Stock. Only bolt in's were allowed. After a friend, who is now deceased, had a rollover and the main hoop punched thru the floorboard, the rules were changed. The accident crushed his vertebrate and he was in a wheel chair until he died, five years later.
Miata roll bars that mount on the package tray in front of the seat belt towers are VERY strong and safe. Any time you can secure it in more than one plane, it is much safer. My newest cage is tied in the same way PLUS a third plate on the side(three plane).
