The whole concept is based on metronomes on a table syncing, or clocks on a wall. That's the proof of concept. Simple.
The fly in the ointment is that the table or wall are stationary and not having external, irregular forces acted on them (like a moving wrist). The same proof of concept needs to be done, but with a moving table or wall. To those that claim a balance isn't the same as a pendulum... It actually is:
It is analogous to the pendulum, according to Wiki so if someone claims otherwise, I need a better source than that.
To say that forces from your wrist don't impact the balance is also unfounded. Frist, if the watch is stopped, just slightly nudging the watch will cause the balance to move. Second, if the watch is ticking and it impacted, it will certainly impact the balances beat rate and/or amplitude (ask a watchmaker). Third, we know that how a watch is worn impacts performance (even the direction it is rested while on a table impacts performance) and we know it impacts performance by its effect on the balance. So watches are certainly impacted by outside forces.
The two balances aren't in the same location so the forces will different that impacts each balance...
But none of that matters. All I keep asking for a simple proof of concept: that the balances will "re-sync" after being out of sync from a nudge or quick flick of the wrist. No one can show this, it seems. And that's fine. I'm not trying to convince anyone that it's a good or bad watch, I'm just stating my personal view of it, so I'm not sure why others are trying to convince me otherwise.
The reality is that, in all industries, there can be a lot of "marketing" and ideas being oversold. Does anyone think that the world of watchmaking is totally exempt from this?