Bluntly, you're giving the Uhaul's CSR reps way more credit than they deserve. What's more likely is that they will hear "mechanical problem" and immediately redirect them to the roadside service team, which essentially is an entirely different part of the company than the Sales/Retail locations. Its actually a case where showing up at a location and "playing dumb" by asking for help, rather than actually calling for help is going to more often than not result in better service.