Isn't the whole idea of bobber stops, especially the top one, so that your float does move and you can fish a slip float. If you don't want your float to move, then why not just peg it?
I have pegged floats before with toothpicks, sometimes they pop out.
A couple of times I had the main line snap (losing everything including float) when fighting a fish.
I remember the last time I ever pegged a float. I set the hook on a steelhead and after one big head shake the fish was gone With my whole rig. Maybe it wasn't the peg but I haven't had it happen since I switched that day so I continue to use stoppers.