I'm pretty sure the scammer tag is not a form of arbitration, it's a warning to others.
There's nothing in arbitration clauses which prevents people from publicly discussing their disputes. To the extent which arbitration clauses are enforceable (which varies by jurisdiction), they only set out agreement regarding the legal procedures for dispute resolution. If arbitration clauses acted as gag orders, you'd never see any criticism of PayPal posted.
+1
I agree with the scammer tag being a warning to others.
Usagi is a double talking scammy fuck who should come with a warning.
This has been proven countless times across many threads.
(Side note: I also went through some bullshit with Usagi and ended up getting the fucking runaround as well.)