When in doubt, demand a written estimate and go down and read it, sign it, get the work done.
In most cases, even if you’re going in for say brake work the technician will do a complete inspection and flag any other issues that require attention. A decent shop should be presenting issues that require immediate repair as such and other maintenance items appropriately. As a business, there’s no good reason not to spend $15 minutes inspecting the rest of the car.
It sounds like your issue though is with the way the shop or the service advisor themselves operate. It’s probably time to find a different service center. Ask questions and give your business to a business that makes you feel comfortable.
As far as legal repercussions, criminal charges would be unlikely. Any actionable claim against them would likely be civil. A local consumer lawyer would be your best bet in that regard.