At the Brussels airport, terrorists wheeled in 3 bombs, but only 2 went off. Now look at this picture:
It has been speculated that the black gloves worn on the left hands of the 2 fellows on the left contained the detonators for the bombs. The man on the right is reportedly the master bomb maker, but seems to have forgotten his glove. This is nothing less than smart gun technology in action. You need your gun and Zut alors! you took off the bracelet/ring/glove required to make it work and now you can't find it.
His fallback strategy was to leave his bomb at the airport and take a taxi home where he was later arrested.