Colin,
In my experience most tire shops are too incompetent to realize that no safety cage is needed to dismount a tire. So - no, most will just lecture you on the danger of split rims without knowing what they're talking about, and refuse to work on them.
Do it yourself. Once the valve stem is out, there is no danger. I've dismounted a few. It's a bit of a workout, but still easier and cheaper than hauling it to a competent tire shop.
