As a previous wheel truck driver and caravan jump seat mechanic - I've only seen it happen a few times and every time it was in big races with caravans and the ability for the rider to jump from car to car and that's after I've gotten word from radio tour and know what my rider is and which wheel is flat - jumped out of the car flying up to the rider with the correct wheel in my hand and a push off after the swap. You don't get that in a local RR with a wheel truck. Every time I have driven a wheel truck the rider hasn't had a chance. just one car and a lot of ground to cover by the time they found their wheel and made a swap - even if I help them.