I should like to clear up how the timing system works.
Just in front of the start line there is a wire over which you all run under and again on the way back. This wire creates a field which reads the transponder on the back of the race number. As you cross the line you would hear a beep which is the system registering you. At the start this beep is almost continuous as there are so many people crossing together but as you finish you should hear an individual beep.
The bats that are waved over the number after you cross the line are a secondary backup in the unlikely event that the finish line field has missed you for some reason. Examples being when people wear their numbers on their back or fold them up. These bats are miniture versions of the primary field and vibrate in the users hand to show that they have read the number. If they don't vibrate it means that the chip has gone dead and then the number can be entered manually. This could be if someone has put their safety pin through the wire. The system will discount all readings from these bats if the runner is picked up on the primary finish, if however somebody is not recorded it will put them in the results from these back up bats between the runners recorded either side
In respect of the start the system is set up and running for quite a while whilst the field is checked etc. It doesn't matter if anyones runs through prior to the race starting as the whole thing is reset about 2 seconds before the guns goes off.