I have no evidence, but I would be absolutely astonished if that were the case.
Rotors and brakes wear out, like tyres, chains and cassettes etc. What would be the value to Decathlon in preventing you from doing your own maintenance on unconnected items?
Opening up the motor, or chipping it - I could see that, but not unconnected items on your bike.
You could always email them and ask, then their reply would give you the evidence you seek.