I recently took a cave rope climbing technique course, after being comfortable with rope climbing in other disciplines, such as climbing, rope rescue and glacier rescue.
The bolting techniques used in caves are fucking terrifying. They work, but they are terrifying.
I'm specifically thinking about using older self-drive bolts, which seem to still be used if they are placed. I have only met people thinking they are acceptable in the caving environment.
And also using temporary bolts as the Coeur 8 mm, which is rated for 2 kN before deformation in the worst direction (and the mechanism of those bolts are more akin to a cam, making them squiggle a lot in the hole, which is safe, but scary. My ice axe don't squiggle).
Obviously you use redundant bolts, and there are much lower forces in SRT than in dynamic falls, but I still think it's scary as hell.
I don't understand, if you are not sure about a two bolt anchor, you can always drill more, rock quality is usually very good. Why do you trust, say an ice axe deadman more than expansion bolts?