I mean the bright orange color is not attached to the rear end of the luggage in this picture. That is unsafe.

And if you wear a yellow reflective vest, it is still possible that a car that crosses your path behind you, touches the rear end of your luggage, because the car driver does not expect that your lugggage is that long. And he/she has to divide his attention to many other vehicles, may be distracted by his smartphone, stress, navigation, bad weather, bad temper, headache, fatigue, alcohol, drugs or whatever. So this car may come from your right or left at a crossing.