Using those ground cables is not just a good idea.
Ground cables - makes me then wonder about their grounding system. Every truck loading terminal that I had worked on had a grounding monitor. The truck grounding cable was connected to the monitor (look up Scully Groundhog). If a proper grounding connection was not maintained, the control logic would not permit product loading.
http://www.scully.com/cgi-bin/pdf/60733_desc.pdf
OSHA is going to be on this one, as well as Texas.
BTW, I do not work for Scully Signal, nor market their products. I am an applications engineer.
You’re just over cautious.