Shops are in the business to create revenue. A good way to create revenue is to sell goods and services to people even if they don't need them. This is especially true if you need to pay for specialty equipment like base grinders and sturcturing tools.
This is a naive response.
The guys at Vancouver Ski and Board services sell what you need, not what they can get away with.
I've had structuring done there and the result was a definite improvement.
No doubt these services got oversold but real shops won't scam you. I've had other shops in Ontario tell me no need to sharpen, we'll just wax it, save you some money. I return to those shops because I trust them.