How you could be cheated while building a gate

So you call in a welder and describe the type and design of gate you want, but the detail is in the type of metals used to build the gate. There are many types of flat sheets, checkered plates, square pipes and rods, plus other different materials for building a gate. Your welder can exploit your limited knowledge if he is sure you don't know the difference. What they do is to promise to use thicker gauge plates and pipes to build your gate, but end up using lighter gauge materials. If they promise you 2.5mm plates, they may use 1.5mm plates in the end. Same for pipes and rods. In the end the gate ends up lighter and less sturdy than what you planned for, and your welder ends up richer.