Perhaps you should read and digest a comment before you get all excited and make responses to points that nobody made.
Any restraint that does REQUIRE a seat belt as any thing other than a very last resort is not fit for purpose. Putting a sprinkler system in a tower block is no substitute for not covering it in flammable cladding.
Properly maintained, operated and designed B&M invert restraints don't rely on their seatbelts as an integral safety feature to their safe operation. How many B&M inverts have you known over 30 years of operation that have solely relied on the seatbelt to get a passenger safely to the break run? B&M don't rely on seatbelts, they rely on well designed restraints that don't need fly open in the first place.
Almost immediately pointing the finger at the lack of seatbelts on this attraction, which is the way the thread was heading, skirts over the fact that it's simply completely unacceptable that any OTSR should be able to release at any point during a rides operation. This is where any sort of investigation will, and should, start - the root cause of what would have prevented the need for any belt to be needed as a failsafe in the first place.