Regarding BMS safety, the reason for removing control of the discharge path is that the device should always prioritize the safety of the user while riding. Instead of dropping the user to the pavement, pushback and audio alerts should be done to alert the user that one of the cells is having a voltage issue, or the pack is getting too hot. Bypassing the BMS's discharge does not effect charge protection, which is the main scenario of what would cause the battery to catch on fire and burn your house down.
In fact, Future Motion DISABLED BEING ABLE TO READ INDIVIDUAL CELL VOLTAGES TO MONITOR THE SAFETY OF THE PACK in an effort to restrict 3rd parties from building batteries. Another anti-consumer decision was the GT having 6.5" non-standard rims in an effort to corner the tire after market. Larger rim size is actually bad for riding characteristics and the right move from an engineering perspective would have been to go smaller actually (the float life is working on 5" hubs)
Yes, I get that having a OneWheel catch on fire impacts their brand, but there's multiple other issues with these devices and quite a number of anti-R2R which is not acting in good faith for users safety, and again, the actual dangerous scenarios are when a cell gets over-charged which the BMS is still there for to enforce. :)
Regarding R2R there's people all around the world who ride these devices, and sending the board into their only location in Cali just isn't an appropriate solution. Unfortunately FM has been very strict on enforcing patents (even though they didn't technically invent the self balancing skateboard as there is prior art) and they have created a anti-competitive, anti-consumer market.
I would absolutely love a safer device that meets the safety standards and certifications you mention, and I hope there can be a path forward where I don't have to build these myself. I'm lazy. I don't exactly enjoy this type of work on my board (I'd rather be riding). I do it out of necessity.