Yeah, I was hoping US Fencing would have more sense than to just copy the FIE's badly thought out specs. International fencers can buy a new strap when they go to international events, if they need to, though I bet if we show them that they work the FIE would adopt magnetic buckles pretty quickly. Regarding the mask coming off in more than one way, I think both failure modes rely on the mask rotating some so the chin pops out of the mask. Then the mask can move either forward or up. The FIE solution, correctly I think, tries to restrict the forward movement of the bottom of the mask when the strap is engaged. If this is correctly designed it should be impossible to take the mask off with the strap in place, and that should prevent both failure modes. Existing mask designs use heavy elastic in the back to hold the mask on. If the strap is going to be fastened with velcro (or a buckle) there's no reason I can see to retain the elastic. It could just be a nylon strap, like a motorcycle chin strap but in the back. Make it adjustable enough to keep the mask on snugly and you're good. The benefit of the elastic was to allow you to remove the mask without unfastening the velcro, which is specifically the thing the new rule is supposed to prevent. I do hope US SEMI takes into account how other high-stakes fastenings like bike and motorcycle helmets work. There's been considerable development of these things since they were invented, and a lot of that would transfer to fencing mask design.