[aedron]

Coinbase could easily avoid, or be unable to, provide BCH balances to their bitcoin holding customers.

There's no telling how Coinbase operates internally. You can't just assume that 1 customer == 1 permanent bitcoin address in Coinbase's backend. Perhaps they shift funds around all the time into new addresses, without keeping references/keys to the old ones. In that case, BCH balances would be lost, with no way to restore them to the 'owner' at the time of the fork.

Luckily (for would-be BCH holders) that seems to not be the case, but I think Coinbase deserves credit for going the extra mile when they could justifiably say that it is not their problem to deal with.

[repomies691]

Anyone can create a new altcoin which starts with bitcoin balances at certain point of the history. If every bitcoin exchange has to support every new altcoin that does that, it would be lots of hassle. I don't think legally the exchanges would be required to provide features for the new altcoins, but it is nice from them if they do.

[elnygren]

> without keeping references/keys to the old ones

You are correct, but this would be a new level of stupid for a leading cyrptocurrency exchange that actually tries to build a reputation and appearance of quality, safety, compliance and being a "legit" service for financial institutions etc.