From your hint, I found http://www.vs.inf.ethz.ch/publ/papers/logtime.pdf
which helps to categorize, what kind of time actually is needed.
For sure there's a difference between systems that can talk in 'frames' (e.g. RTS) and one that seems to be continous in time (like a flightsim).
I always try to live with 'roughly synced clocks', so that I can use timestamps that mean at least something, if not the true time. But I admit that it is hard to deal with that.
Object may die remote before I see that I hit them and so on.
Really difficult. For games, maybe its a good strategy to cheat and fake. Taking time into account more or less, depending on what looks better in a particular case