I can't believe in this day and age some shops still 'tuner lock' ECMs.
Some high horsepower race thing, sure, that's your secrets and a compleltley different level of tuning..
A gen 3 sierra with a cam only. There is no reason for that at all.
Didn't even tell the customer before they did it. To me, this is sort of 'stealing' by not allowing the owner to go forth with another shop to make different adjustments, like gear ratio or tire size changes.
Please don't tuner lock, it looks bad on the shop.