I'm not going to be much help here, but I will do the best I can to tell you what I do know. Ocn can probably elaborate on this better than me.
There are four methods that I know that people use to remove pinstripes: a stripe-off wheel, a razor blade, spray-on chemicals, or a heat gun.
The razor blade is for DIYers who don't feel like slapping down $10 bucks on a stripe-off wheel or $50 to $100 bucks for a heat gun, so it's pretty much safe to say that I don't think any professional body shops use this particular method. You can cause clear coat damage using a razor blade after all.
The 3M Stripe-Off Wheel is a giant rubber disc that is attached to a shank. DIYers and professionals alike use them because they can be used in power tools capable of spinning at least 4000rpms, like a power drill or Dremel tool. They can also be used in combination with a Large Area Stripe Remover disc for things like large decals, etc. Now, I will caution that the SOW can not only remove pinstripes, but burn clear coat off as well. It's fairly difficult not to on old, cracking pinstripe. I removed the pinstripe on my old '98 S-10 with a SOW in an old power drill and wound up burning the clear coat off of the passenger side front quarter panel (it did great everywhere else). With such little age on that Buick, though, I think there would be little chance for that happening. Whoever uses one should use it very carefully.
The heat gun is another method that leaves a fair amount of chance of not allowing the adhesive of the pinstripe to remove sections of clear coat. I would also expect some professional bodyshops to use this method as well.
There's also spray on products from 3M (GP Adhesive Remover, Decal and Woodgrain Remover) that can remove pinstripes quite safely as well. Sometimes these products can break down pinstripe to where it takes a rag, some elbow grease, and a good hand wash to get them off.
I would ask your dealer if they can remove the stripes and then ask exactly what method they use to remove them. Use your best judgment based on what they tell you.
If I'm telling him something monumentally wrong, someone step in and correct me. I know how much it sucks to remove pinstripe and damage the clear in the process.