People clamping a bar 26.0 size probably had problems. I can also vouch that the Modolo stems had issues. I had a Modolo stem where the stem bolt gave when I hit a bump in the road. I got really bad road rash but luckily no serious damge.

Don't worry those stems are safe. Don't over tighten the wedge or it could crack. Don't grease the wedge area...Just put a tiny bit on the stem itself and it will be fine.