As the Member Liaison at Catalyst Fitness, I put weight plates back on the weight stands when they are left on machines and barbells on stands. Many times I find the plates in the wrong peg.  There are various reasons why but it may be members don’t know the correct locations.  At one time our weight stands probably had labels on the ends of each peg.  45, 35, 25, 10, 5,2.5  are the weights.   All gyms I’ve been it have this same arrangement.  Below is my video explaining the correct weight placement.