If you're transacting with an exchange or a merchant and accidentally send both coins (as a result of a replay attack) instead of one, they're going to give it back. It's not nearly the disaster this article makes it out to be.
The only case where this is a problem are business to consumer transactions and p2p txs both of which you rarely do, if ever if you use BTC as a store of value.
The only case where this is a problem are business to consumer transactions and p2p txs both of which you rarely do, if ever if you use BTC as a store of value.