of course You have the right to inspect your vehicle at the store before paying for repairs. However, this does not give you the right to remove the vehicle from the shop without paying for repairs, or to inspect it in areas where only authorized employees are allowed.
What if there is a violation of the regulations regarding the repair of the vehicle?
the DMV will take action against the store. This may include suspending or revoking the store registration and / or imposing fines. If you suffer a financial loss due to a surcharge or unnecessary or poor quality repairs, the administrative law judge presiding over the hearing may offer the store the option to pay restitution. The store may receive a shorter suspension period and / or a lower fine. DMV cannot compel a store to pay restitution.
And how do I know that they are charging me just enough?