... I think we need more careful about detect alt account, we shouldn't tag someone by suspicion only (IMO). Transaction made on each other also not strong proof of alt account. We can exchange something each others, so it would not consider alt account also.
I have said the same thing several times on the "Known Alts" thread... Just because one or more ETH addresses send tokens to another ETH address, does not make them all Alts... but no-one listens, they're already off on their
And as coinlocket$ has so neatly highlighted here... even trying to use multiple BTC addresses used as inputs in a single transaction only proves that those addresses are from the same wallet, but doesn't actually confirm wallet ownership.
As this case shows, with regards to gambling or exchange sites, deposit addresses (and the wallet containing them) are actually owned by the sites... not by the individual users... so there is no way that you can link two users of a given site as being alt accounts based on their BTC deposit addresses for that site.