By locking, do you guys mean how they tighten during the ride? Swarm’s still tightened noticeably last time I rode it in August 2019, so I’m not sure if Merlin had their wing coasters retrofitted.
To be honest, I don’t actually dislike B&M’s vest restraints. While they do tighten, they’re not the only restraints I’ve known to do that, and I wouldn’t say it majorly inhibits my enjoyment of the ride, personally. Olympia Looping’s shoulder bars tightened to a far more enjoyment-restricting degree for me, and even the Mack lap bars on Icon do tighten as the ride goes on, although as with Swarm, I don’t find this tightening inhibits the enjoyment for me.
What is it that everyone seems to hate so much about them on Inverted Coasters and Dive Coasters?