I think a lot of it is just wanting to make sure the workorder is accurate so the tech has the correct equipment and can complete the install in one trip.
That's the other thing. Customers act like the ONLY thing we carry on our vans are the required receiver for just THEIR work order. I laugh all the time when I have to Modify and the customer asks if I have the equipment to do today.
Typically my van has 6 ea Hopper 3's and 2's, 1 2000, 10 Joey 2's and 3's, 8 Wireless Joeys, a 211, a 722, 4 Wallys and 4 Duos and 4ea of Joey 4 and Wireless Joey 4's not to mention all the WAP's Hughesnet and Viasat modems and Trias and 10 ea of Eastern and Western Hybrids, 3 ea of each arc DPP and 2 Int'l. LNB's. Then there are the Dish kits, masts, poles, other mounts, and gear like RF modulators, flat cables, tools... Plus the SHS stuff we sell. Mounts, Polks Systems, Google/Nest stuff....
Trust me, techs show up ready for anything