In the example of a radar track, if we received one given event whose timestamp is before the latest we persisted, it means we can simply discard it.
This way, we can simply decide to not store it at all (because it would break a rule upfront) or to ignore it during the rehydration process.
So, it is something which can be done but per event.
Nice post. Yet, in my opinion microservices architecture should be based (as much as possible) on asynchronous interactions. One of the main idea between this architecture is to favor autonomy over authority. Synchronous interactions result in increasing the coupling and losing autonomy.