Block the transaction, yes of course, I'm not against that, but don't block the whole card from use! What if you're, like, stuck abroad and are relying on it?

When my cards have detected an unreliable transaction, they block the transaction, and then call me to confirm. I can still use the card for other transactions at other stores. In one case, the card was used as a store where a series of cards has been skimmed so they proactively sent me a new card, but didn't deactivate the old card until I had activated the new card.