Eduardo,
This is a very good question that many clubs and home racers handle differently.
There is no right or wrong way to handle deslots during a race. You must decide how you will handle them when you are racing with your son or others.
Here are a few methods that we have tried or are currently using with our group of racers:
1. Manual Corner Marshaling Method: Corner marshals "reslot" the cars, and the racing action does not stop. This works when you have enough corner marshals available to monitor the problem areas of the track. We do not use this method with our group of guys, because we don't have enough extra guys to act as corner marshals.
2. "Impartial Marshal" Method: One of our racers - a controls engineer - developed an electronic system that automatically monitors each lane for the presence of a car. If a car deslots, this system, which we refer to as the "Impartial Marshal" automatically shuts down power to all lanes through power relays and pauses the PC Lap Counter program. A reset button is pushed which restores power to all lanes after a programmable amount of time (1, 2, 3 sec, etc.) At the same time, it unpauses the PC Lap Counter program. A negative aspect of this system is that you cannot use controller braking when using the system.
3. Crash-and-Burn Method: Each driver is allowed "X" number of deslots for the entire race, where "X" might be 1, 2 or 3. If the driver reaches the maximum number of deslots, his race is over. This method might seem harsh, but the intent is to promote more careful driving. If one driver deslots and causes another driver to deslot, our club rule is that only the driver-at-fault is charged with a deslot. Some clubs set the rules such that it doesn't matter who is at fault - a deslot is a deslot.
Our group of racers use the Impartial Marshal system along with a Crash-and-Burn rule that allows "3" deslots per race.
I'm sure other methods could be used along with PC Lap Counter, such as invoking a stop-and-go penalty each crash, but these methods require an extra person available to be practical.
I'm open to hearing about other methods that racers are using, but the above methods are the ones I have used through the years.
Hope this helps you, Eduardo.
Foiler in MI