[punky]

You don't need to go to replays like Hawkeye and the cricket. It can be done seemlessly

For example. Eduardo dives and the ref immediately gives a penalty. Its a good minute or two before the player steps up to take the penalty. The replays are instant and in the minute or so the 4th official can clearly see there is no contact. So during the run up to the penalty the 4th official can contact the ref on the radio and tell him he dived. Eduardo is booked and play goes on. Play isn't interrupted any more so than the natural flow.

It only needs to be done for game changing moments. I.e. goals and sending off. It doesn't need to be if a player dives in the middle of the field.