Then you'll need to deal with it.
But again, it's highly unlikely both would start at the same time.
If each of them kick start on average every 20 minutes, and they take 2 seconds to start:
20 minutes x 60 seconds = 1200 seconds
2 seconds / 1200 = 1/600th chance they start at the same time in a single 20 minute session. 600 attemps (in 20 minute spans) is 500 days