Event Sourcing can be as consistent as any other data source. For a hotel booking company, I'd have each hotel be a unique aggregate stream, and with expected

Event Sourcing can be as consistent as any other data source. For a hotel booking company, I'd have each hotel be a unique aggregate stream, and with expected version assertion, a ReserveRoom Command for a room would only succeed if the latest state had an opening for that room. As soon as someone successfully reserves a room, all further reserve commands fail until another event frees up the room. The expected version assertion on writes guarantees this.